[RESTRICT AUTOMERGE][pm] prevent system app downgrades of versions lower than preload am: 224da6d4c2

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/21159679

Change-Id: If3a608061f82434fed162d56a01ae5eac5229af4
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>