docs: add Android push notification guidance to Expo README section

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: Rosie-Kennelly-1

README.md

@@ -660,6 +660,10 @@ Add the necessary permission descriptions to infoPlist key.
 
 Next, rebuild your app as described in the ["Adding custom native code"](https://docs.expo.io/workflow/customizing/) guide.
 
+The Expo plugin automatically generates a `FirebaseMessagingService` for Android that routes Intercom pushes to the SDK and passes non-Intercom messages through to other handlers (e.g. `expo-notifications`).
+
+> **Note**: If your app uses another SDK that registers its own `FirebaseMessagingService` (e.g. OneSignal, Braze), list `@intercom/intercom-react-native` **before** that SDK in your `plugins` array. This allows the plugin to detect the other service and skip its own registration, avoiding conflicts.
+
 #### Expo: Push notification deep links support
 
 > **Note**: You can read more on Expo [documentation](https://docs.expo.dev/guides/deep-linking)

src/expo-plugins/withAndroidPushNotifications.ts

@@ -128,17 +128,6 @@ const writeFirebaseService: ConfigPlugin<IntercomPluginProps> = (_config) =>
     },
   ]);
 
-/**
- * Adds the FirebaseMessagingService entry to the AndroidManifest.xml
- * so Android knows to route FCM events to our service.
- *
- * If another FirebaseMessagingService is already registered (from another
- * SDK or manual setup), skips registration and warns. Note: due to Expo's
- * LIFO mod execution order, this detection only works when the conflicting
- * plugin is listed AFTER @intercom/intercom-react-native in the plugins
- * array. If your app has another FCM-handling SDK, list Intercom first
- * in the plugins array to ensure conflict detection works correctly.
- */
 const registerServiceInManifest: ConfigPlugin<IntercomPluginProps> = (
   _config
 ) =>