Fix security vulnerability when register phone accounts. am: 833dd8480a

Original change: https://googleplex-android-review.googlesource.com/c/platform/packages/services/Telecomm/+/20028194

Change-Id: I5d66d0975945d27a7df5c9078f5e345e42b7c915
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>