Merge "Add/fix null-check on ringtoneSupplier." into udc-dev am: 29528d51

Original change: https://googleplex-android-review.googlesource.com/c/platform/packages/services/Telecomm/+/22290825



Change-Id: I8d2b6366d5e02508ebe9f42b8a9fab630be990c7
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>