Check system and phone UID in multiple-user-aware way am: 1879bc3033 am: b7d4b51edc

Original change: https://android-review.googlesource.com/c/platform/packages/modules/Connectivity/+/3163003

Change-Id: I65df150f80d661494370e5c735db108622876539
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>