Backport issue count badge style refactor for re-use from EE related issues

What does this MR do?

• Backport issue count badge style refactor for re-use from EE related issues, https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/1797

Added by https://gitlab.com/gitlab-org/gitlab-ee/commit/88aea2cbc8633ba970335d935d725bd17654b424

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?