add class css on column actions in view list

Resources/views/CRUD/list__action.html.twig

@@ -1,4 +1,4 @@
-<td>
+<td class="sonata-ba-list-field sonata-ba-list-field-action">
     {% for actions in field_description.options.actions %}
         {% include 'SonataAdminBundle:CRUD:list__action' ~ actions ~ '.html.twig' %}
     {% endfor %}