Merge branch '481673-remove-unsed-css-classes-from-issuable-list' into 'master'

Audit list of classes in page_bundles/issues_list.scss

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/164636



Merged-by: Martin Wortschack <mwortschack@gitlab.com>
Approved-by: Vanessa Otto <votto@gitlab.com>
Approved-by: Martin Wortschack <mwortschack@gitlab.com>
Co-authored-by: Deepak kumar <kumar.deepak.iiit@gmail.com>