add frozen field to schema (#31199)

> No issue, just something I noticed

# Checklist for submitter

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

<!-- Note that API documentation changes are now addressed by the
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- [x] Manual QA for all new/changed functionality

ee/maintained-apps/inputs/homebrew/schema/input-schema.json

@@ -75,6 +75,10 @@
       "description": "A filepath to an uninstall script. If provided, this script will override the generated uninstall script.",
       "minLength": 1,
       "pattern": "\\.sh$"
+    },
+    "frozen": {
+      "type": "boolean",
+      "description": "If true, the app will not be processed during ingestion and no new output will be created."
     }
   },
   "not": {