Resolve "CI status icon and avatar are not vertically aligned in MR list"

What does this MR do?

Fix the author icon's vertical align. See: https://gitlab.com/gitlab-org/gitlab-ce/issues/39607

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

I haven't found any list with the author_link class where we should use the display: block CSS rule, but please confirm it.

Why was this MR needed?

To fix the author icon's vertical align in the issues and the MR list pages.

Screenshots (if relevant)

MR's list before:

MR's list after:

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• Documentation created/updated
• API support added
• Tests added for this feature/bug
• Review
  • Has been reviewed by UX
  • Has been reviewed by Frontend
  • Has been reviewed by Backend
  • Has been reviewed by Database
• Conform by the merge request performance guides
• Conform by the style guides
• Squashed related commits together
• Internationalization required/considered
• End-to-end tests pass (package-qa manual pipeline job)

What are the relevant issue numbers?

Closes #39607 (closed)