signInOAuth method
Starts a OAuth sign-in flow for provider using Firebase.
The instance of FirebaseAuth will be from the default Firebase App
Unless withApp is used to build an instance
It will return authentication result OAuthCredential.
If supported by Firebase, this will contains the provider access
token as accessToken.
Implementation
@override
Future<OAuthCredential> signInOAuth(String provider, List<String> scopes,
[Map<String, String>? customOAuthParameters]) =>
_delegate.signInOAuth(provider, scopes, customOAuthParameters);