Replace spaceless twig filters with apply spaceless

Closes #3484750

templates/widget-entity-content-add-list.html.twig

@@ -14,10 +14,10 @@
  * @ingroup themeable
  */
 #}
-{% spaceless %}
+{% apply spaceless %}
   <dl>
     {% for type in types %}
       <dt>{{ type.link }}</dt>
     {% endfor %}
   </dl>
-{% endspaceless %}
+{% endapply %}