fix Modify commit message button spacing

What does this MR do?

Remove .spacing class that was removing right margin

Remove wrapper span around Button that affected vertical alignment

Screenshots (if relevant)

Does this MR meet the acceptance criteria?

• 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 #3163 (closed)