Add UID permission check to update_engine am: 596969b84d am: 4465217f5a

Original change: https://android-review.googlesource.com/c/platform/system/update_engine/+/2774952

Change-Id: I151678d01b78daf7064196e356ddb01a589b2c99
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>