Fix S and T mixed build OTA am: 1c4b981c71

Original change: https://android-review.googlesource.com/c/platform/system/update_engine/+/2058027

Change-Id: I17866f8597c87f45c49f256594276da6c8a29449
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>