Fix package loading.

The basic PackageManager query didn't always return all the packages we
cared about. Change to query for each specific user and indicate that we
want all packages, regardless of user-unlock status.

Bug: 158300259
Test: atest FrameworksMockingServicesTests:AgentTest
Change-Id: Idd1f15078545f99bdccb2cdc26806c904e2f1eae