Firebase Crashlytics 적용

https://pub.dev/packages/firebase_core
https://pub.dev/packages/firebase_crashlytics

void main() async {
  WidgetsFlutterBinding.ensureInitialized();
  await Firebase.initializeApp(); // firebase core 초기화
  runZonedGuarded(() { // firebase crashlytics
    setUp();
    runApp(const MyApp());
  }, FirebaseCrashlytics.instance.recordError);
}

FirebaseCrashlytics.instance.crash()로 실행 후 파이어베이스에서 확인