Collect camera power consumption into BatteryStats

Plumb through the camera energy consumption from Power Stats HAL to
BatteryStatsImpl. Allowing clients to query global and per-uid stats
will be done in follow-up changes.

Bug: 258319905
Change-Id: I9d5243164e388a90f6d1ceb9345e893cf1aa5f1d
Test: atest BatteryStatsTests