Fix modal tab navigation for wagtail 2.13

wagtailvideos/templates/wagtailvideos/chooser/chooser.html

@@ -3,7 +3,7 @@
 {% include "wagtailadmin/shared/header.html" with title=choose_str merged=1 tabbed=1 icon="media" %}
 
 {% if uploadform %}
-    <ul class="tab-nav merged">
+    <ul class="tab-nav merged" data-tab-nav>
         <li class="{% if not uploadform.errors %}active{% endif %}"><a href="#search" >{% trans "Search" %}</a></li>
         <li class="{% if uploadform.errors %}active{% endif %}"><a href="#upload">{% trans "Upload" %}</a></li>
     </ul>