Add shared nested_documentable specs to admin dashboard actions specs.

Not render Documents count on dashboard actions views.
Add skips on nested_documentable when factory_name is equal to dashboard_actions.

spec/features/admin/dashboard/actions_spec.rb

@@ -7,6 +7,15 @@ feature 'Admin dashboard actions' do
     login_as(admin.user)
   end
 
+  it_behaves_like "nested documentable",
+                  "administrator",
+                  "dashboard_action",
+                  "new_admin_dashboard_action_path",
+                  { },
+                  "documentable_fill_new_valid_dashboard_action",
+                  "Save",
+                  "Action created successfully"
+
   context 'when visiting index' do
     context 'and no actions defined' do
       before do