MediaMetricsService: Use system_clock for TimedAction

This ensures AudioPowerUsage atoms are delivered
based on wallclock time.

Test: adb shell dumpsys media.metrics --all
Bug: 314810064
Merged-In: Ic98e6b48602f61792c40b21d57b809596fa136ff
Change-Id: Ic98e6b48602f61792c40b21d57b809596fa136ff
2 files changed