Migrate app/assets/javascripts/work_items/components/work_item_links/okr_actions_split_button.vue to GlDisclosureDropdown or GlCollapsibleListbox

One or more dropdowns in app/assets/javascripts/work_items/components/work_item_links/okr_actions_split_button.vue should be migrated to one of the new dropdown components. See the parent epic &10695 for guidance on migration strategies.