Merge "Add comments stating the configs for visible background users are not ready for production" into udc-dev am: 5191e0d75c am: 208bd1824c

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/24140525

Change-Id: I531a999f9b73efb9fc3966d0d11c15566e06596d
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>