feat: extend authentication to expose the `idTokenChange` event

[cjhoward92]

Plugin(s)

• [ ] Analytics
• [ ] App
• [ ] App Check
• [X] Authentication
• [ ] Crashlytics
• [ ] Cloud Firestore
• [ ] Cloud Functions
• [ ] Cloud Messaging
• [ ] Cloud Storage
• [ ] Performance
• [ ] Remote Config

Current problem

The idTokenChange event is not exposed. Also. on iOS, the auth change listener isn't correct. It should be like so https://firebase.google.com/docs/auth/ios/manage-users

Preferred solution

Do the things.

Alternative options

There are none - we need this.

Additional context

• Android: https://firebase.google.com/docs/reference/android/com/google/firebase/auth/FirebaseAuth.IdTokenListener#onIdTokenChanged(com.google.firebase.auth.FirebaseAuth)
• iOS: https://firebase.google.com/docs/reference/swift/firebaseauth/api/reference/Classes/Auth#/c:@M@FirebaseAuth@objc(cs)FIRAuth(im)addIDTokenDidChangeListener:
• Web: https://firebase.google.com/docs/reference/js/auth.md#onidtokenchanged_b0d07ab

Before submitting

• [X] I have read and followed the feature request guidelines.
• [X] I have attached links to possibly related issues and discussions.

[robingenz]

Also. on iOS, the auth change listener isn't correct.

What exactly is wrong with it? This listener is already used by many apps without any problems.