Implement new system note icons
EE version
https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/2713
All icons updated
mention
assignee
label
issue closed
issue open
milestone
confidential
non-confidential (visible)
task done
title/desc changed
branch
move to another project
commit
merge
discusions resolved
duplicate
What are the relevant issue numbers?
Closes #33503 (closed)
Edited by username-removed-408230