Fix log statements in cleanup container repository worker

🌲 Context

We are monitoring what the ContainerExpirationPolicies::CleanupContainerRepositoryWorker using logs.

One thing, we're looking is the cleanup_status value in logs.

When it's done or unfinished, this attribute will be in the log as json.extra.container_expiration_policies_cleanup_container_repository_worker.cleanup_status.

However, when we are in the skipped case, this attribute will appear as json.cleanup_status.

What does this MR do?

• Properly log the skipped cleanup_status.
• Update the related specs accordingly

Screenshots (strongly suggested)

n / a

Does this MR meet the acceptance criteria?

Conformity

• [-] Changelog entry
• [-] Documentation (if required)
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• [-] Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.
• [-] Tested in all supported browsers
• [-] Informed Infrastructure department of a default or new setting change, if applicable per definition of done

Security

If this MR contains changes to processing or storing of credentials or tokens, authorization and authentication methods and other items described in the security review guidelines:

• [-] Label as security and @ mention @gitlab-com/gl-security/appsec
• [-] The MR includes necessary changes to maintain consistency between UI, API, email, or other methods
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