Adjust NullifyOrphanRunnerIdOnCiBuilds batch parameters

What does this MR do and why?

ref: !81410 (comment 874179914)

This MR will adjust NullifyOrphanRunnerIdOnCiBuilds batch parameters.

In GitLab.com, migration jobs took more than 2 minutes with 100k batch size and 1k sub batch size. Also initiated an incident gitlab-com/gl-infra/production#6581 (closed)

So, we decided to start lower than those parameters.

• Decrease batch_size to 50_000 to get an immediate effect so that it adjusts to going higher automatically.
• Increase pause_ms to 200.
• Decrease sub_batch_size to 500.

Also, we will allow the batch size to increase up to 150k if it's possible.

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