[automerger skipped] [DO NOT MERGE] Fix Settings crash when setting a null ringtone am: d94b73b304 am: 58880a0bef -s ours

am skip reason: subject contains skip directive

Original change: https://googleplex-android-review.googlesource.com/c/platform/packages/apps/Settings/+/18356598

Change-Id: Ie868f286a337b9c1612820424d0bdc8f2c488c70
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>