Remove Rotation uma

The metric is expired and not monitored. Removing the metric. Leaving
the trace for local debugging.

OBSOLETE_HISTOGRAM[Android.Rotation.BeginToRendererFrameActivation]=expired and
unneeded.

Bug: 41497378
Change-Id: If60c05388bf0c533beb468e77c2a771a01dca716
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5605633


Reviewed-by: Michael Thiessen <mthiesse@chromium.org>
Commit-Queue: Jonathan Ross <jonross@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1312183}