Add aidl_interface for update_engine am: 6d8a94df0c

Original change: https://android-review.googlesource.com/c/platform/system/update_engine/+/3290648

Change-Id: If7c6a73bc0246db2ae74cdc71c5f5c84c098d6d1
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>