Add a field to ServiceRecord for FGS notification permissions.

This field will be logged in the pushed atom for FGS state changes in a future CL, and will help us understand how often a foreground service runs without permission to post notifications.

This change adds areNotificationsEnabledForPackage to NotificationManagerInternal for ease of access via ServiceRecord.

Bug: 194833441
Test: NMSTest, NotificationPermissionMigrationTest, manual for ServiceRecord

Change-Id: I543e68479d57f197937a22217668840dfed1429e