Prevent non-admin users from deleting system apps. am: 6c870e1579 am: 15ab50ec29 am: d719add201

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

Change-Id: Ibc618f6b6c33f0635acb6aae640e31a04044645b
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>