GitLab Pages: Fix rubocop issues

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What does this MR do and why?

When working on !162835 (merged), I saw potential to also fix some rubocop issues along the way. In order to keep !162835 (merged) focussed, I decided to extract the rubocop fixes in a separate MR.

This MR needs to wait for GitLab Pages: Add error handling to method #cha... (!162835 - merged).

🛠 with ❤ at Siemens

MR acceptance checklist

Please evaluate this MR against the MR acceptance checklist. It helps you analyze changes to reduce risks in quality, performance, reliability, security, and maintainability.

MR Checklist (@gerardo-navarro)

• Changelog entry added, if necessary
• Documentation created/updated via this MR
• Documentation reviewed by technical writer or follow-up review issue created
• Tests added for this feature/bug
• Tested in all supported browsers
• Conforms to the code review guidelines
• Conforms to the merge request performance guidelines
• Conforms to the style guides
• Conforms to the javascript style guides
• Conforms to the database guides
• Wait for !162835 (merged)

Screenshots or screen recordings

Only backend change. No frontend change.

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Related to #467235