Merge "Fix group cast volume slider not disabled after switching to group...

Merge "Fix group cast volume slider not disabled after switching to group devices." into tm-dev am: e94f1590

Original change: https://googleplex-android-review.googlesource.com/c/platform/packages/apps/Settings/+/17351353



Change-Id: I6bd64e363b0e24fe2a81859cc00669c16846c26a
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>