Make sure callingPackage belongs to callingUid when checking BG-FGS restrictions.

This is to stop spoofed packageName to pretend to be allowListed
packageName so it can bypass the BG-FGS restriction. This applies to
both BG-FGS while-in-use restriction and BG-FGS-start restriction
since these two restrictions are related.

Bug: 216695100
Bug: 215003903
Test: atest cts/tests/app/src/android/app/cts/ActivityManagerSpoofTest.java
Change-Id: Ic14fc331a9b5fbdbcfe6e54a31c8b765513bfd89