Revert "Add UID permission check to update_engine" am: eceec328e2 am: 4c2cb8a5da

Original change: https://android-review.googlesource.com/c/platform/system/update_engine/+/2776588

Change-Id: I4945b19a613537d82c9c3fee104f1bdeb5211a3d
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>