Allow-while-idle alarms throttling for app standby

Started throttling allow_while_idle alarms again. Throttled
allow_while_idle alarms behave as if the scheduling app scheduled it at
the next eligible time, so there is no conflict with app standby
rescheduling. Also exempting alarms by mSystemUiUid from app standby

Test: atest CtsAlarmManagerTestCases:AppStandbyTests

Bug: 72660630
Bug: 72916765
Change-Id: Ibb8ab449e1c148fc9689f1c2afb89b8d9630edfa