Trigger notes refresh in specs instead of waiting for ajax

spec/features/issues/note_polling_spec.rb

@@ -10,7 +10,7 @@ feature 'Issue notes polling' do
 
   scenario 'Another user adds a comment to an issue', js: true do
     note = create(:note_on_issue, noteable: issue, note: 'Looks good!')
-    sleep 15 # refresh interval in notes.js.coffee is 15 seconds
+    page.execute_script('notes.refresh();')
     expect(page).to have_selector("#note_#{note.id}", text: 'Looks good!')
   end
 end