Remove external link support in sub navigation

This navigation will only have internal links in it.

app/templates/components/sub-navigation.html

@@ -3,22 +3,17 @@
 ) %}
   <nav class="sub-navigation">
     <ol itemscope itemtype="http://schema.org/ItemList">
-      {% for item in item_set %}        
-        <li class="sub-navigation__item {% if item['link'] == request.endpoint %} sub-navigation__item--active {% endif %}" 
-            itemprop="itemListElement" 
-            itemscope 
+      {% for item in item_set %}
+        <li class="sub-navigation__item {% if item['link'] == request.endpoint %} sub-navigation__item--active {% endif %}"
+            itemprop="itemListElement"
+            itemscope
             itemtype="http://schema.org/ListItem"
         >
-          <a href="{%- if item['external_link'] -%} 
-                     {{ item['link'] }} 
-                   {%- else -%} 
-                     {{ url_for(item['link']) }} 
-                   {%- endif -%}" 
-             itemprop="item">
+          <a href="{{ url_for(item['link']) }}" itemprop="item">
             <span itemprop="name">{{item['name']}}</span>
           </a>
         </li>
       {% endfor %}
     </ol>
   </nav>
-{% endmacro %}
+{% endmacro %}