CirrusSearch: disable saneitizer cron job
We see an increased DB activity on S3, which is probably related to a bug
in the CirrusSearch saneitizer job. Disabling this cron should release
the DB load if needed.
We are working on a real fix, so unless situation degrades, we will not
merge this change. But in case we need it, it is ready.
Bug: T143862
Change-Id: I8c68a4a8f63a58b777eb80d899dc3f3b5b71fd38