title: Firebase - can't set title and message of notification
body: <p>From my PHP server I sent this notification data to Firebase API:</p>
  
  <pre><code>$fields = [
      'to' =&gt; "fcm....",
      'notification' =&gt; [
          'title' =&gt; 'Test Test Test',
          'body' =&gt; 'MSG MSG MSG'
      ],
      'data' =&gt; [
          'type' =&gt; 'message',
          'sender' =&gt; 'someone'
      ],
      'priority' =&gt; 'high'
  ];
  </code></pre>
  
  <p>In android studio, this is the <code>MyFirebaseMessagingService</code> class that extends the <code>FirebaseMessagingService</code> class:</p>
  
  <pre><code>public class MyFirebaseMessagingService extends FirebaseMessagingService {
      @Override
      public void onMessageReceived(RemoteMessage remoteMessage) {
          sendNotification("Test", "Test");
      }
  
      private void sendNotification(String title, String message) {
          Intent intent = new Intent(this, MainActivity.class);
          intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
          PendingIntent pendingIntent = PendingIntent.getActivity(this, 0, intent,
                  PendingIntent.FLAG_ONE_SHOT);
  
          String channelId = getString(R.string.notification_channel_id);
          Uri defaultSoundUri= RingtoneManager.getDefaultUri(RingtoneManager.TYPE_NOTIFICATION);
          NotificationCompat.Builder notificationBuilder =
                  new NotificationCompat.Builder(this, channelId)
                          .setSmallIcon(R.drawable.notificatino)
                          .setContentTitle(title)
                          .setContentText(message)
                          .setAutoCancel(true)
                          .setSound(defaultSoundUri)
                          .setContentIntent(pendingIntent);
  
          NotificationManager notificationManager =
                  (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);
  
          if (Build.VERSION.SDK_INT &gt;= Build.VERSION_CODES.O) {
              NotificationChannel channel = new NotificationChannel(channelId,
                      "Channel human readable title",
                      NotificationManager.IMPORTANCE_DEFAULT);
              notificationManager.createNotificationChannel(channel);
          }
  
          notificationManager.notify(0, notificationBuilder.build());
      }
  }
  </code></pre>
  
  <p>The problem is I keep get notifications with the title and message from the server (Title Title Title, MSG MSG MSG) instead of get notifications with the title and message I have passed to <code>sendNotification</code> as arguments:</p>
  
  <p><a href="https://i.stack.imgur.com/kMBlg.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/kMBlg.png" alt="The notification I receive not including the title and message I have passed to the function"></a></p>