Revert "Change the Ambient Context Manager to return STATUS_SERVICE_UNAVAILABLE instead of STATUS_NOT_SUPPORTED when the detection service is not set up."

This reverts commit 49938fc385.

Reason for revert: the owner (kxchen@) says their client relies on STATUS_NOT_SUPPORTED to know whether AiAi service is available. And she will change the status code logic with some other improvements.

Change-Id: I64785f224ded5b8f6b3d26f6865d5c1a017ad9d6

services/core/java/com/android/server/ambientcontext/AmbientContextManagerPerUserService.java

@@ -220,7 +220,7 @@ final class AmbientContextManagerPerUserService extends
             } else {
                 Slog.w(TAG, "No valid component found for AmbientContextDetectionService");
                 sendStatusToCallback(clientStatusCallback,
-                        AmbientContextManager.STATUS_SERVICE_UNAVAILABLE);
+                        AmbientContextManager.STATUS_NOT_SUPPORTED);
             }
         }
     }