Do not allow low light ambient monitoring when on battery.

This changelist ensures that low light monitoring does not occur when
on battery.

Test: atest LowLightBehaviorCoreStartableTest#testDoNotSubscribeIfDozingForScreenOffBehaviorUnplugged
Fixes: 428556986
Flag: EXEMPT bugfix
(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:e6249b76ada538812b1ff119d556d166571d1568)
Merged-In: I466505654ebed4da10b65f553d4d33aced453304
Change-Id: I466505654ebed4da10b65f553d4d33aced453304