Potential: Update PipelineHooksWorker to utilize new Sidekiq readonly database replicas capabilities

With the ability to Allow Sidekiq jobs to use readonly database replicas in place, the next step will be to enable this capability for this worker.

It appears that this worker isn't entirely read-only; occasionally, we see writes being logged:

https://log.gprd.gitlab.net/goto/40c15f1a6c04291037de9a77c4c422a3

However, during that week these 85 writes only made up 0.0008% of all ~11M successful executions. It is unclear what these writes are, but it is likely safe to migrate this worker to read from replicas primarily.