Move FinishedSnapshotWrites call to filesystem verifier am: 5b00dc5386

Original change: https://android-review.googlesource.com/c/platform/system/update_engine/+/2601565

Change-Id: Ifabc169312f1a32ce10250021ee66da30b486c3d
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>