Enable alarm permission with a soft failure mode

Introducing a switch to change to logging whenever a caller without
permission schedules an alarm-clock or exact, allow-while-idle alarm.
This will help us catch pathological breakages before we actually harden
the restriction.

Also adding systemui's uid to the exemption list.

Test: atest CtsAlarmManagerTestCases

Bug: 171306433
Change-Id: I641ec064a03fca8de9f4726b4d728a5608596ef3