Use context's userId in ContentResolver class.

- When registering and notifying observers, we should use the user in the
context as opposed to current user.
- Relax the permission check while registering and notifying content observers
to use INTERACT_ACROSS_USERS instead of INTERACT_ACROSS_USERS_FULL permission.

Change-Id: I973936903d4a2272c5722f3b98a057a40c0402be
Fixes: 32955100
Test: Created managed profile and verified that there are not failures.
      runtest -x core/tests/coretests/src/android/content/SecondaryUserContentResolverTest.java
      runtest -x core/tests/coretests/src/android/content/ManagedUserContentResolverTest.java