Merge "Don't restore notification channel if its sound is unavailable" into sc-dev am: c4646c09 am: 68339bcb am: 2c33cbb9

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/14424418

Change-Id: If4a16048234612c7d0b31767ae415c999559ec92