openSignInFlow 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
Implementation
@override
Future<User?> openSignInFlow(String provider, List<String> scopes,
[Map<String, String>? customOAuthParameters]) async {
final oAuthProvider = web.OAuthProvider(provider);
scopes.forEach((scope) => oAuthProvider.addScope(scope));
if (customOAuthParameters != null) {
oAuthProvider.setCustomParameters(customOAuthParameters);
}
await web.app(_app().name).auth().signInWithPopup(oAuthProvider);
return FirebaseAuth.instanceFor(app: _app()).currentUser;
}