Add safeguard fot the spec failure

https://github.com/railsadminteam/rails_admin/runs/7385621766?check_suite_focus=true

Author: mshibuya

spec/integration/fields/ck_editor_spec.rb

@@ -24,6 +24,7 @@
     visit new_path(model_name: 'player')
     find_link('Add a new Comment').trigger 'click'
     expect(page).to have_text 'New Comment'
+    expect(page).to have_css '.cke_button__link'
     find('.cke_button__link').click
     expect(page).to have_css '.cke_dialog_ui_input_text'
     first(:css, '.cke_dialog_ui_input_text').click