Merge "[Output Switcher] Disable volume control if route is volume_fixed" into tm-dev am: 25639f1b6d

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/18756771

Change-Id: Ic11bc62236f85cdb873c1dc25b10232251a5d3d8
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>