[native] Set badge count on Android in native code

Summary: Move setting the count from js to native. We're using the same functions as RNFirebaseNotifications for setting the count. The benefit of this is that we no longer display an empty notification for badge only notifs, as they do not reach the js.

Test Plan: Send a message and mark a thread as read and unread while monitoring the badge count value that is set by the methods. The issue with this is that I was not able to see the badge count on an Android simulator. It looks like this is only supported by vendors https://github.com/leolin310148/ShortcutBadger/issues/174.

Reviewers: karol-bisztyga, atul, ashoat

Reviewed By: ashoat

Subscribers: benschac, ashoat, Adrian

Differential Revision: https://phabricator.ashoat.com/D3069