Fix interval option in occ background-job:worker

[salmart-dev]

Summary

Context

This PR comes from an investigation done for issue #49584

The user reported that running occ background-job:worker --interval 5 does not run jobs every 5 seconds as advertised.
Upon investigation, I found out that the implementation for the --interval option was never merged and the option seems to be a leftover from the PR where background workers were introduced.

This PR makes uses the passed interval and follows the behaviour described in the parameter's description.

Checklist

• Code is properly formatted
• Sign-off message is added to all commits
• Tests (unit, integration, api and/or acceptance) are included
• Screenshots before/after for front-end changes
• Documentation (manuals or wiki) has been updated or is not required
• Backports requested where applicable (ex: critical bugfixes)

[salmart-dev]

/backport to stable31

[nickvergessen]

Breaking change

[github-actions]

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[nickvergessen]

Please update PR title and description to the actual content change

[salmart-dev]

Please update PR title and description to the actual content change

Done

[salmart-dev]

/backport to stable32

[nickvergessen]

You pushed a fixup commit, can you merge that into the intended commit @salmart-dev