fix(auth): fixing scopes and parameters that would not work for GoogleAuthProvider (#13018)

Author: Lyokone

packages/firebase_auth/firebase_auth_platform_interface/lib/src/method_channel/utils/convert_auth_provider.dart

@@ -34,5 +34,13 @@ AuthProvider convertToOAuthProvider(AuthProvider authProvider) {
     return oAuthProvider;
   }
 
+  if (authProvider is GoogleAuthProvider) {
+    final oAuthProvider = OAuthProvider(authProvider.providerId);
+    oAuthProvider.setScopes(authProvider.scopes);
+    oAuthProvider
+        .setCustomParameters(authProvider.parameters.cast<String, String>());
+    return oAuthProvider;
+  }
+
   return authProvider;
 }