Remove blank block from job sidebar

What does this MR do?

Remove the blank block that was displayed in the job sidebar in some cases:

before	after

This block was being rendered depending on the output of the renderBlock() function, but the function was out of sync with what's shown in the block, so there were some cases where the function returned true based on something that is no longer used in the block (job.merge_request, job.cancel_path, etc.)

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry
• [-] Documentation created/updated or follow-up review issue created
• Code review guidelines
• Merge request performance guidelines
• Style guides
• Database guides
• [-] Separation of EE specific content

Performance and testing

• Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.
• Tested in all supported browsers

Closes #59521 (closed)