Fix security vulnerability when register phone accounts. am: 833dd8480a am: 581e22326e

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

Change-Id: I41cf54d81f1c9deddc29f8e3d47327d23cbc036c
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>