DPMS: Fix Device Admin-related caller identity checks

When there's a Device Admin on a device with a work profile, two
operations will fail:
* Calling isActivePasswordSufficient from the work profile.
* Trying to remove the Device Admin.

isActivePasswordSufficient would fail because it uses an incorrect
variant to check whether an admin is a Profile Owner. That variant fails
when checking admins from the primary profile.

getRemoveWarning fails because it incorrectly does not let the system
(UID 1000) to call it.

This CL fixes both issues.

Bug: 173578428
Bug: 173481459
Test: Manual, with TestDPC: Create a work profile, add a Devide Admin on
the primary profile, check that TestDPC can start and report password
sufficiently correctly, then the Device Admin can be removed.
Test: atest com.android.cts.devicepolicy.ManagedProfileTest
Test: atest com.android.cts.devicepolicy.MixedManagedProfileOwnerTest#testResetPasswordWithToken

Change-Id: Ie4665fc86fc17d116ffadde3e4e5732c71da13f7