Link to libsnapshot dynamically. am: 62b0c3c6c8

Original change: https://android-review.googlesource.com/c/platform/system/update_engine/+/2670281

Change-Id: Ib8f6dd3a7006b0afe2e339bef607a621293cddfa
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>