What does this MR do?
It fixes + aligns the styling of multi select user items. Spacing + Bold + @ sign changed. I thought about aligning it with the styling of single select but the avatar has s24 on purpose so it looks like a deliberate decision to have the one line format (which makes sense cause you see more results at once).
Screenshots (if relevant)
Does this MR meet the acceptance criteria?
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?
Closes #33981 (moved)