fix the long button in the bootstrap advanced options UI (#38567)

**Related issue:** Resolves #37003

This fixes the long button in the bootstrap package advanced options
section.

- [x] Added/updated automated tests

frontend/pages/ManageControlsPage/SetupExperience/cards/BootstrapPackage/components/BootstrapAdvancedOptions/BootstrapAdvancedOptions.tsx

@@ -79,6 +79,8 @@ const BootstrapAdvancedOptions = ({
                     Install Fleet's agent (fleetd) manually
                   </TooltipWrapper>
                 </Checkbox>
+                {/* The wrapper div is needed to keep the button from stretching full width
+                 * of the flex container */}
                 <div>
                   <Button
                     disabled={

frontend/pages/ManageControlsPage/SetupExperience/cards/BootstrapPackage/components/BootstrapAdvancedOptions/_styles.scss

@@ -14,8 +14,4 @@
     flex-direction: column;
     gap: $pad-large;
   }
-
-  .button {
-    width: fit-content;
-  }
 }