On android devices only, when I send a push notification via firebase cloud messaging, the icon attached to the notification is a blank white circle. I am doing the FCM functionality in a custom backend API call, not the native flutterflow one. You can see I have attached what the notifications look like as well as what my FCM payloads are structured like (essentially copied from the flutterflow implementation with some small differences). What is the solution to get my android device to display the app icon on push notifications?