Rework starting settings activity from Volume Panel bottom bar.

The problem is that ActivityStarterImpl overrides flags passed within
the Intent. This CL ensures that Intent.FLAG_ACTIVITY_REORDER_TO_FRONT
reaches the activity startup.

Flag: aconfig new_volume_panel TRUNKFOOD
Test: manually on the phone. Open settings from the Volume Panel
Bug: 330814968
Change-Id: Idda64e37e1fc9f0e442fe89abbdbd2336ffc5558