Add epic to the scope and fix the flaky spec

ee/lib/gitlab/elastic/group_search_results.rb

@@ -31,7 +31,7 @@ def scope_options(scope)
         case scope
         when :users
           super.except(:group_ids) # User uses group_id for namespace_query
-        when :wiki_blobs, :work_items
+        when :wiki_blobs, :work_items, :epics
           super.merge(root_ancestor_ids: [group.root_ancestor.id])
         else
           super

ee/spec/features/search/elastic/group_search_spec.rb

@@ -86,15 +86,13 @@ def choose_group(group)
       choose_group(group)
     end
 
-    it 'finds epics', quarantine: 'https://gitlab.com/gitlab-org/gitlab/-/issues/500148' do
-      # issues
+    it 'finds epics' do
       submit_search('chosen')
       select_search_scope('Epics')
       expect(page).to have_content('chosen epic title')
     end
 
     it 'finds issues' do
-      # issues
       submit_search('chosen')
       select_search_scope('Issues')
       expect(page).to have_content('chosen issue title')

ee/spec/lib/gitlab/elastic/group_search_results_spec.rb

@@ -498,6 +498,18 @@
       end
     end
 
+    context ':work_items' do
+      it 'has root_ancestor_ids' do
+        expect(subject.scope_options(:work_items)).to include :root_ancestor_ids
+      end
+    end
+
+    context ':epics' do
+      it 'has root_ancestor_ids' do
+        expect(subject.scope_options(:epics)).to include :root_ancestor_ids
+      end
+    end
+
     context ':wiki_blobs' do
       it 'has root_ancestor_ids' do
         expect(subject.scope_options(:wiki_blobs)).to include :root_ancestor_ids