consistent padding on new MR panels

What does this MR do?

More consistent spacing on commits, for both Panels and Rows

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

• do we still need -webkit-flex?
• .table-list classes were only used by commit. Ok to delete?
• .commit.flex-list used for styling because I couldn't think of a class name. Please suggest if you can

Screenshots (if relevant)

New MR

Does this MR meet the acceptance criteria?

• Changelog entry added
• Documentation created/updated
• API support added
• 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?

Empty state spacing from #28426 (closed) Closes #28230 (closed)