update_engine: cow estimator to use cow version am: 51983150f3 am: 60abcaca11 am: 64efabccfb

Original change: https://android-review.googlesource.com/c/platform/system/update_engine/+/2887466

Change-Id: Ia3774eef89b2005bf86930dd5f3636e3ce8b84ed
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>