main function Null safety
Main program initializes Firebase, configures EmailAuthProvider, and runs FirebaseAuthUIExample.
Implementation
Future<void> main() async {
WidgetsFlutterBinding.ensureInitialized();
await Firebase.initializeApp(options: DefaultFirebaseOptions.currentPlatform);
FirebaseUIAuth.configureProviders([EmailAuthProvider()]);
runApp(const FirebaseAuthUIExample());
}