[#29014] Create issue form buttons are misaligned on mobile

What does this MR do?

Fixes button alignment issue for Create Issue page during mobile responsive https://gitlab.com/gitlab-org/gitlab-ce/issues/29014 Cancel button should align with the Create Issue

Are there points in the code the reviewer needs to double check?

Why was this MR needed?

Fix for https://gitlab.com/gitlab-org/gitlab-ce/issues/29014

Screenshots (if relevant)

After fix

Does this MR meet the acceptance criteria?

• Changelog entry added
• Tests
  • 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?

https://gitlab.com/gitlab-org/gitlab-ce/issues/29014

Closes #29014 (closed)