feat: Allow setting the self-avatar

packages/moxplatform_android/lib/src/notifications_android.dart

@@ -25,6 +25,11 @@ class AndroidNotificationsImplementation extends NotificationsImplementation {
     return _api.showMessagingNotification(notification);
   }
 
+  @override
+  Future<void> setNotificationSelfAvatar(String path) async {
+    return _api.setNotificationSelfAvatar(path);
+  } 
+
   @override
   Stream<NotificationEvent> getEventStream() => _channel
       .receiveBroadcastStream()