Fix spacing between MR number and title

What does this MR do?

Fixes spacing between MR number and title when MR number is higher than 9999.

Why was this MR needed?

See #29560 (closed)

Screenshots

Before

After

Does this MR meet the acceptance criteria?

• [ ] Changelog entry added
• [ ] Documentation created/updated
• [ ] API support added
• Tests
  • [ ] Added for this feature/bug
  • All builds are passing
• Conform by the merge request performance guides
• Conform by the style guides
• Branch has no merge conflicts with master (if it does - rebase it please)
• Squashed related commits together

What are the relevant issue numbers?

Closes #29560 (closed)