fix misaligned ref. indications table

scipost_django/submissions/templates/submissions/_hx_referee_indication_table.html

@@ -89,7 +89,7 @@
   {% empty %}
  
     <tr>
-      <td colspan="6" class="text-center">No referee indications created yet.</td>
+      <td colspan="20" class="text-center">No referee indications created yet.</td>
     </tr>
 
   {% endfor %}