Expire job and pipeline cache synchronously

What does this MR do and why?

Expires the job and pipeline cache synchronously instead of in Sidekiq jobs. This allows us to avoid the overhead of Sidekiq scheduled jobs. These are scheduled jobs (1 second in the future) because these are set to read from a DB replica.

This also makes the ETag polling actually "work" because currently scheduled jobs have a latency of ~20 seconds.

More details in gitlab-com/gl-infra/scalability#1380 (closed)

MR acceptance checklist

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