Send a broadcast when an app is granted SCHEDULE_EXACT_ALARM

Bug: 187206399
Test: atest AlarmManagerServiceTest
Test: Manual test with a test app.
- Grant the permission to test app and make sure it can start FGS.
Log:
```
05-07 10:12:08.671  1000  1579  9475 I ActivityManager: Background started FGS: Allowed [callingPackage: com.google.omakoto.testapp; callingUid: 10294; uidState: RCVR; intent: Intent { act=fgs cmp=com.google.omakoto.testapp/.MyFgs }; code:(unknown:207); tempAllowListReason:<broadcast:1000:android.app.action.SCHEDULE_EXACT_ALARM_PERMISSION_STATE_CHANGED,reason:,reasonCode:(unknown:207),duration:10000,callingUid:1000>; targetSdkVersion:30; callerTargetSdkVersion:30; startForegroundCount:0]
```
- Grant the permission to a different app and make sure the test app
  won't receive the broadcast.

Test: CTS -- Incoming

Change-Id: Iefe3e12dcf51318d8433532ba3048caa69b1edcd