Unrestricting app when put on power whitelist

Power whitelisting and background restrictions are opposing rules, so to
keep apps out of confusing states, unrestricting an app whenever it is
put on the power whitelist.

Test: atest RunSettingsRoboTests:HighPowerDetailTest

Bug: 77924141
Change-Id: I4952ac6c893bc7e98aa1b6ad3a86906fc299dea5