Code dropdown: Migrate to GlDisclosureDropdown (Part 2)

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/143324



Merged-by: Paul Gascou-Vaillancourt <pgascouvaillancourt@gitlab.com>
Approved-by: Annabel Dunstone Gray <annabel.dunstone@gmail.com>
Approved-by: Paul Gascou-Vaillancourt <pgascouvaillancourt@gitlab.com>
Reviewed-by: Annabel Dunstone Gray <annabel.dunstone@gmail.com>
Reviewed-by: Paul Gascou-Vaillancourt <pgascouvaillancourt@gitlab.com>
Reviewed-by: Alper Akgun <aakgun@gitlab.com>
Reviewed-by: Sascha Eggenberger <seggenberger@gitlab.com>
Co-authored-by: Sascha Eggenberger <seggenberger@gitlab.com>