Fixed Android Enterprise page not refreshing (#45914)

<!-- Add the related story/sub-task/bug number, like Resolves #123, or
remove if NA -->
**Related issue:** Resolves #45862 

Speculative fixes since I wasn't able to repro issue locally.
Refresh AppContext and the React Query ["config"] cache directly after
the SSE/DELETE response so AndroidMdmCard and AndroidMdmPage flip
without a manual page reload, with a bounded retry to defeat the 1s
cached_mysql.AppConfig TTL. Also harden startSSE to detect the success
signal across chunk boundaries and reject (rather than hang) when the
stream ends without it.

# Checklist for submitter

If some of the following don't apply, delete the relevant line.

- [x] Changes file added for user-visible changes in `changes/`,
`orbit/changes/` or `ee/fleetd-chrome/changes`.
See [Changes
files](https://github.com/fleetdm/fleet/blob/main/docs/Contributing/guides/committing-changes.md#changes-files)
for more information.

- [x] Timeouts are implemented and retries are limited to avoid infinite
loops

## Testing

- [x] QA'd all new/changed functionality manually

For unreleased bug fixes in a release candidate, one of:

- [x] Confirmed that the fix is not expected to adversely impact load
test results

<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit

* **Bug Fixes**
* Fixed Android Enterprise page not refreshing after connecting or
disconnecting Android MDM. The Enterprise ID and card state now update
automatically without requiring a manual page reload.

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changes/45862-android-enterprise-page-refresh

@@ -0,0 +1 @@
+- Fixed Android Enterprise page not refreshing after connecting or disconnecting Android MDM, so the Enterprise ID and card state are visible without a manual page reload.

frontend/pages/admin/IntegrationsPage/cards/MdmSettings/AndroidMdmPage/AndroidMdmPage.tsx

@@ -6,11 +6,12 @@ import React, {
   useState,
 } from "react";
 import { InjectedRouter } from "react-router";
-import { useQuery } from "react-query";
+import { useQuery, useQueryClient } from "react-query";
 
 import PATHS from "router/paths";
 import { AppContext } from "context/app";
 import { NotificationContext } from "context/notification";
+import { IConfig } from "interfaces/config";
 import { getErrorReason } from "interfaces/errors";
 import mdmAndroidAPI from "services/entities/mdm_android";
 import { DEFAULT_USE_QUERY_OPTIONS, SUPPORT_LINK } from "utilities/constants";
@@ -37,6 +38,8 @@ interface ITurnOnAndroidMdmProps {
 
 const TurnOnAndroidMdm = ({ router }: ITurnOnAndroidMdmProps) => {
   const { renderFlash } = useContext(NotificationContext);
+  const { setConfig } = useContext(AppContext);
+  const queryClient = useQueryClient();
 
   // TODO: figure out issue with aborting the SSE fetch when the window is closed
   const newWindow = useRef<Window | null>(null);
@@ -48,18 +51,33 @@ const TurnOnAndroidMdm = ({ router }: ITurnOnAndroidMdmProps) => {
     async (abortController: AbortController) => {
       try {
         await mdmAndroidAPI.startSSE(abortController.signal);
-        abortController.abort();
-        renderFlash("success", "Android MDM turned on successfully.", {
-          persistOnPageChange: true,
-        });
-        setSetupSse(false);
-        router.push(PATHS.ADMIN_INTEGRATIONS_MDM);
       } catch {
         renderFlash("error", "Couldn't turn on Android MDM. Please try again.");
         setSetupSse(false);
+        return;
       }
+      abortController.abort();
+      // SSE success means the backend has already set
+      // android_enabled_and_configured=true. Patch the in-memory config so
+      // AppContext.isAndroidMdmEnabledAndConfigured flips immediately and
+      // AndroidMdmCard renders correctly on redirect, without a synchronous
+      // round-trip.
+      const prevConfig = queryClient.getQueryData<IConfig>(["config"]);
+      if (prevConfig) {
+        const patched: IConfig = {
+          ...prevConfig,
+          mdm: { ...prevConfig.mdm, android_enabled_and_configured: true },
+        };
+        setConfig(patched);
+        queryClient.setQueryData(["config"], patched);
+      }
+      renderFlash("success", "Android MDM turned on successfully.", {
+        persistOnPageChange: true,
+      });
+      setSetupSse(false);
+      router.push(PATHS.ADMIN_INTEGRATIONS_MDM);
     },
-    [renderFlash, router]
+    [queryClient, renderFlash, router, setConfig]
   );
 
   useEffect(() => {

frontend/pages/admin/IntegrationsPage/cards/MdmSettings/AndroidMdmPage/components/TurnOffAndroidMdmModal/TurnOffAndroidMdmModal.tsx

@@ -1,9 +1,12 @@
 import React, { useCallback, useContext, useState } from "react";
 import { InjectedRouter } from "react-router";
+import { useQueryClient } from "react-query";
 
 import PATHS from "router/paths";
 import mdmAndroidAPI from "services/entities/mdm_android";
+import { AppContext } from "context/app";
 import { NotificationContext } from "context/notification";
+import { IConfig } from "interfaces/config";
 
 import Modal from "components/Modal";
 import Button from "components/buttons/Button";
@@ -20,6 +23,8 @@ const TurnOffAndroidMdmModal = ({
   router,
 }: ITurnOffAndroidMdmModalProps) => {
   const { renderFlash } = useContext(NotificationContext);
+  const { setConfig } = useContext(AppContext);
+  const queryClient = useQueryClient();
 
   const [isDeleting, setIsDeleting] = useState(false);
 
@@ -27,15 +32,28 @@ const TurnOffAndroidMdmModal = ({
     setIsDeleting(true);
     try {
       await mdmAndroidAPI.turnOffAndroidMdm();
-      renderFlash("success", "Android MDM turned off successfully.", {
-        persistOnPageChange: true,
-      });
-      router.push(PATHS.ADMIN_INTEGRATIONS_MDM);
     } catch (e) {
       onExit();
       renderFlash("error", "Couldn't turn off Android MDM. Please try again.");
+      return;
     }
-  }, [onExit, renderFlash, router]);
+    // DELETE success means the backend has already cleared
+    // android_enabled_and_configured. Patch the in-memory config so the
+    // parent MDM page's card flips immediately on redirect.
+    const prevConfig = queryClient.getQueryData<IConfig>(["config"]);
+    if (prevConfig) {
+      const patched: IConfig = {
+        ...prevConfig,
+        mdm: { ...prevConfig.mdm, android_enabled_and_configured: false },
+      };
+      setConfig(patched);
+      queryClient.setQueryData(["config"], patched);
+    }
+    renderFlash("success", "Android MDM turned off successfully.", {
+      persistOnPageChange: true,
+    });
+    router.push(PATHS.ADMIN_INTEGRATIONS_MDM);
+  }, [onExit, queryClient, renderFlash, router, setConfig]);
 
   return (
     <Modal title="Turn off Android MDM" className={baseClass} onExit={onExit}>

frontend/services/entities/mdm_android.ts

@@ -44,18 +44,32 @@ export default {
         });
 
         const reader = response?.body?.getReader();
+        if (!reader) {
+          reject(new Error("Android MDM SSE stream unavailable"));
+          return;
+        }
         const decoder = new TextDecoder();
+        const successSignal = "Android Enterprise successfully connected";
+        // Buffer accumulates decoded text so a success message split across
+        // multiple chunks (valid with chunked transfer encoding) is still
+        // detected.
+        let buffer = "";
 
         while (true) {
-          // @ts-ignore
           // eslint-disable-next-line no-await-in-loop
-          const { done, value } = await reader?.read();
-          if (done) break;
-          const text = decoder.decode(value);
-          if (text === "Android Enterprise successfully connected") {
-            resolve();
-            break;
+          const { done, value } = await reader.read();
+          if (done) {
+            // Server closed the stream without ever sending success.
+            // Reject so callers don't await forever on unmount or backend hiccup.
+            reject(new Error("Android MDM SSE ended before success signal"));
+            return;
           }
+          buffer += decoder.decode(value, { stream: true });
+          if (buffer.includes(successSignal)) {
+            resolve();
+            return;
+          }
+          buffer = buffer.slice(-successSignal.length);
         }
       } catch (error) {
         if ((error as Error).name === "AbortError") {