Cap the duration of StaleManagersCleanupService to 4 minutes

What does this MR do and why?

Describe in detail what your merge request does and why.

This MR introduces a cap on the time that can be spent by Ci::Runners::StaleManagersCleanupService deleting stale runners. This ensures that we don't spend any error budget.

Part of #412298 (closed)

Screenshots or screen recordings

Screenshots are required for UI changes, and strongly recommended for all other merge requests.

Before	After

How to set up and validate locally

Numbered steps to set up and validate the change are strongly suggested.

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.