update_engine: remove temporary estimation am: 018bcd79f1

Original change: https://android-review.googlesource.com/c/platform/system/update_engine/+/2954478

Change-Id: Ica40f583f1f3592de3fb094371361aa72b936b34
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>