the AddUsagesForPage job can be de-duplicated better, based primarily on title + parser language code.
This would help avoid unnecessary and redundant updates to the wbc_entity_usage table. For example, in cases where an item or a client page is edited again when we still have older jobs in the queue, then the older jobs can become no-ops and we execute only the most recent job for a page (+parser language).
even if the usages didn't change, we still update the touched timestamp, and want to avoid database updates like this when unnecessary.