Update otapreopt_script to support Async Pre-reboot Dexopt.

Bug: 377557749
Test: -
  1. system/update_engine/scripts/update_device.py out/dist/$TARGET_PRODUCT-ota-$USER.zip
  2. adb shell cmd jobscheduler run android 27873781
Change-Id: I4fc7c4a08516bc48a69cfe7e01402838b27dfdea