Merge "Remove the fallback AddSupervisedUserActivity." into tm-dev am: 15a89a60ac am: 2ecf96a422

Original change: https://googleplex-android-review.googlesource.com/c/platform/packages/apps/Settings/+/20665167

Change-Id: I6474b049eea96fa6b51692a71ea7a2433cdfb620
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>