revert: restore safe filter for extra head HTML injection

Author: fpichardom

ckanext/digitizationknowledge/templates/base.html

@@ -8,5 +8,5 @@
 
 {% block head_extras %}
 {{ super() }}
-{{ h.get_extra_head_html() }}
+{{ h.get_extra_head_html() | safe }}
 {% endblock %}