Validate ringtone URIs before setting am: 7ba175eaeb am: 236f1a0f17

Original change: https://googleplex-android-review.googlesource.com/c/platform/packages/apps/Settings/+/24956689

Change-Id: Ifcec90852c0369ee58dabfd2fb9cf4f45fc2e2c4
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>