RESTRICT AUTOMERGE: Allow System user to call getRegistration API.

Bug: 336976105
Test: Verified on CF that only system server is able to bind.
Ignore-AOSP-First: Backporting fix
Flag: EXEMPT Mainline module change.
(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:d9c9db03fae63ac16d76cd68450e78c4a9285104)
Merged-In: I6ee570b9c432ece71442cb989dd37cf5df35dc55
Change-Id: I6ee570b9c432ece71442cb989dd37cf5df35dc55