Clear notifications for packages whose permission is revoked

This is a rollforward of ag/24038746, with two differences:
* Ignore onOpChanged callbacks for non-initialized users. We realized this is being called for all packages on first start.
* Only send the ACTION_APP_BLOCK_STATE_CHANGED broadcast on manual changes coming form Settings. This is less "theoretically correct" than the previous CL, but added in the event there are more cases where onOpChanged is called unexpectedly.

Test: atest NotificationManagerService + manual
Fixes: 288651621
Change-Id: I7222cdbd09d51523ab16fe44a3c12dfdce0e7365