Update BatteryUtils to update system battery estimate cache

To try and ensure SysUI and Settings don't show different battery
estimates we have settings always push the estimate to the system
cache which will cause the status bar to update as well.

Test: manually trigger battery broadcasts and observe
Bug: 124030091
Change-Id: I07a17ecf2a42c3022673ad2aca438f8d6e81b41f