Merge "Remove volume_separate_notification flag" into udc-dev am: 7aa8424c am: 23383b3c

Original change: https://googleplex-android-review.googlesource.com/c/platform/packages/apps/Settings/+/23244447



Change-Id: I5e62c876235e37288ac2a2640f4752d3a985d9de
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>