FR:app share extension share firestore data with container app in ios

### Feature proposal

* Firebase Component: Firestore

I have a container app use firestore store data, and I want my app share extension read data from firestore when client is offline
I read the both firebase and apple doc carefully and find this api [appGroupID](https://firebase.google.com/docs/reference/swift/firebasecore/api/reference/Classes/FirebaseOptions#/c:objc(cs)FIROptions(py)appGroupID). so I try config appGroupID in `FirebaseApp.configure()`. but still failed.

Is there a way to achieve it? This problem has been bothering me for several days