Remove unnecessary span in approvals footer

What does this MR do?

Fixes vue template that was causing [Vue warn] in karma

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

Just make sure it's okay for us to remove the </span> versus adding a <span>

Why was this MR needed?

As found in https://gitlab.com/gitlab-org/gitlab-ee/builds/12840324 by @nick.thomas

Screenshots (if relevant)

None

Does this MR meet the acceptance criteria?

• 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?

None