Merge branch 'tree-table-class-migration' into 'master'

Tree table: Migrate classes used to design tokens

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/171722



Merged-by: Janis Altherr <jaltherr@gitlab.com>
Approved-by: Annabel Dunstone Gray <annabel.dunstone@gmail.com>
Approved-by: Serhii Yarynovskyi <syarynovskyi@gitlab.com>
Approved-by: Janis Altherr <jaltherr@gitlab.com>
Co-authored-by: Michael Becker <mbecker@gitlab.com>