[FIrebase Auth] add oauth2 missing functionality from other platofrms

[prggTheProgrammer]

So recently Oauth support for providers like microsoft was added. But I noticed that there are still some things that I want to do that are available on all other platforms. I think it makes sense for these things to be added to flutter as well. I am talking about two things:

• add reauthenticateWithAuthProvider method If a user goes out of your app and then comes back, the user is automatically signed in, but you still need to get the access token. With a method like this (that already exists in other platforms: https://firebase.google.com/docs/auth/ios/microsoft-oauth#handle_the_sign-in_flow_with_the_firebase_sdk) you can get the access token without having to sign out and sing in the user. (see https://stackoverflow.com/questions/71179133/get-access-token-with-flutterfire-after-user-is-signed-in)

• Include the access token in AuthCredential In the old firebase plugin you could get the access token (in my case I want to get the ms-graph access token) from the OAuthCredential returned from the signinWithPopup method. But now you get a AuthCredential which does not have a access token ([📚] Get ms graph access token from flutterfire signInWithAuthProvider method #9505)

[prggTheProgrammer]

Support for these things were added