Fixes DPMS.getEnforcingAdminAndUserDetailsInternal()

It was not properly setting the admin when the user restriction was
set by both DPC and system (for example, location being disabled for
work profile by Settings).

Similarly, RestrictedLockUtilsInternal.checkIfRestrictionEnforced()
was not setting the EnforcedAdmin user when there were multiple
sources.

Test: manual verification using CtsVerifier

Bug: 128928355
Fixes: 208501696

Change-Id: Ia0c1489ba0eadd67b9a8e802eb8640c9c1236e44