Align milestone column header with count number

What does this MR do?

• Aligns the milestone column header with the count number
• Prevents the count from wrapping below the column header

Why was this MR needed?

• Count number was being pushed below the column header text if the text was too long

Screenshots (if relevant)

• see issue sceenshots for before #25810 (closed)
• fixed version

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 #25810 (closed)