lingo: add <div> for correct spacing of self declared invoice cell (#13751)

combo/apps/lingo/templates/lingo/combo/self-declared-invoice-payment.html

@@ -1,5 +1,6 @@
 {% load i18n %}
 {% if title %}<h2>{{ title }}</h2>{% endif %}
+<div>
 {% if text %}<p>{{ text|safe }}</p>{% endif %}
 <form class="quixote" action="{% url 'lingo-self-invoice' cell_id=cell.id %}">
   <div class="widget">
@@ -25,3 +26,4 @@
     <button>{% trans "Pay" %}</button>
   </div>
 </form>
+</div>