当应用程序在后台运行或关闭时，Flutter Firebase消息在IOS上不起作用

<key>NSLocalNotificationUsageDescription</key>
<string>This app requires access to send notifications.</string>
<key>NSMicrophoneUsageDescription</key>
<string>This app requires access to the microphone.</string>

import UIKit
import Firebase

@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {

    var window: UIWindow?

    func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
        FirebaseApp.configure()
        return true
    }

    func application(_ application: UIApplication, didReceiveRemoteNotification userInfo: [AnyHashable : Any], fetchCompletionHandler completionHandler: @escaping (UIBackgroundFetchResult) -> Void) {
        // Handle the notification
    }
}

dependencies:
  firebase_core: ^2.0.0
  firebase_messaging: ^10.0.0

import 'package:firebase_core/firebase_core.dart';
import 'package:firebase_messaging/firebase_messaging.dart';

void main() async {
  WidgetsFlutterBinding.ensureInitialized();
  await Firebase.initializeApp();
  FirebaseMessaging.onBackgroundMessage(_firebaseMessagingBackgroundHandler);
  runApp(MyApp());
}

Future<void> _firebaseMessagingBackgroundHandler(RemoteMessage message) async {
  // Handle the background message
  print("Handling a background message: ${message.messageId}");
}