chore: hide official assemblies in breadcrump

src/plainui/jinja2/plainui/event.html.j2

@@ -33,9 +33,11 @@
         <li class="breadcrumb-item">
           <a href="{{ url('plainui:index') }}">{{ conf.name }}</a>
         </li>
+        {% if not assembly.is_official %}
           <li class="breadcrumb-item">
             <a href="{{ url('plainui:assemblies') }}">{{ _("assemblies") }}</a>
           </li>
+        {% endif %}
         <li class="breadcrumb-item">
           <a href="{{ url('plainui:assembly', assembly_slug=assembly.slug) }}">{{ assembly.name }}</a>
         </li>