Merge "Trim strings added to persistent snoozed notification storage." into sc-dev am: 999e19b8

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/21740239



Change-Id: I70add930510da4f3aeb653e0baf25f65fe43b8f0
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>