Play customer sound notification when app is killed in flutter

[priyesh-bit]

Foreground custom notification sound is completely working

But when app is killed or in background then it sound mobile default notification.

{
  "to" : token,
  "collapse_key" : "type_a",
  "priority" : "high",
  "notification" : {
    "body" : "Test Notification",
    "title": "Custom sound",
    "sound": "alert.mp3",
    "android_channel_id": "noti_push_app_1",
    "content_available": true,
  }
};

---

var android = new AndroidNotificationDetails(
    'sdffds dsffds',
    "CHANNLE NAME",
    "channelDescription",
    importance: Importance.max,
    priority: Priority.max,
    enableLights: true,
    playSound: true,
    sound: RawResourceAndroidNotificationSound('alert'),
  );

MainActivity.kt

import io.flutter.embedding.android.FlutterActivity

class MainActivity: FlutterActivity() {
}