Allow disable_vabc flag in full OTA am: 413982e445 am: 8b76e5667b

Original change: https://android-review.googlesource.com/c/platform/system/update_engine/+/1613459

MUST ONLY BE SUBMITTED BY AUTOMERGER

Change-Id: I35d0de803e4f643b6fc35729094238713d248c40