Throttle metric writing by 3 seconds am: 32a73a96d1 am: aa806fb19b

Original change: https://android-review.googlesource.com/c/platform/system/update_engine/+/2363989

Change-Id: Ifac920f4bbf7f69342584016f0d1ff65be82b1b6
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>