Prevent non-admin users from deleting system apps. am: 6c870e1579

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/17408864

Change-Id: I40bc39502ae92a42aa44a6ed89fb4079aec52048
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>