Merge "libsnapshot: Check for valid snapshots based on current slot" into main...

Merge "libsnapshot: Check for valid snapshots based on current slot" into main am: acdc4848 am: 8ef208f7 am: fccfcec2

Original change: https://android-review.googlesource.com/c/platform/system/core/+/2701654



Change-Id: I423050f5b64cbdbb4675f45b5ee163ea5627243c
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>