[RESTRICT AUTOMERGE][pm] prevent system app downgrades of versions lower than preload am: cc9d3867

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/21160027



Change-Id: Ie6541f3bc09669a23ac0762d655342c3a7930561
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>