[automerge] Trim strings added to persistent snoozed notification storage. 2p:...

[automerge] Trim strings added to persistent snoozed notification storage. 2p: b8a07871 am: 5768ea22 am: 02a68596 am: 7b557292

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



Change-Id: I580cd6452bdbf352780755a47eccfd626fc627bc
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>