Fix Vue 3 specs

Add check for null and undefined

app/assets/javascripts/work_items/components/work_item_assignees.vue

@@ -117,7 +117,9 @@ export default {
         if (!data) {
           return;
         }
-        this.localUsers = unionBy(this.localUsers, [data.currentUser], 'id');
+
+        const currentUsers = data.currentUser ? [data.currentUser] : [];
+        this.localUsers = unionBy(this.localUsers, currentUsers, 'id');
       },
     },
   },

scripts/frontend/quarantined_vue3_specs.txt

@@ -246,5 +246,4 @@ spec/frontend/vue_shared/directives/tooltip_on_truncate_spec.js
 spec/frontend/vue_shared/directives/track_event_spec.js
 spec/frontend/vue_shared/issuable/sidebar/components/issuable_sidebar_root_spec.js
 spec/frontend/webhooks/components/push_events_spec.js
-spec/frontend/work_items/components/work_item_assignees_spec.js
 spec/frontend/work_items/components/work_item_description_rendered_spec.js