Always offer option to add new sender

Not sure why we had this logic. We shouldn’t make you jump over to the
settings page if none of the available options are right for this
letter.

app/templates/views/templates/set-template-sender.html

@@ -23,9 +23,7 @@
           hide_legend=True
         ) }}
         {{ page_footer('Continue') }}
-        {% if no_senders %}
-          <a href="{{ url_for('.service_add_letter_contact', service_id=current_service.id, from_template=template_id) }}">Add new sender</a>
-        {% endif %}
+        <a href="{{ url_for('.service_add_letter_contact', service_id=current_service.id, from_template=template_id) }}">Add new sender</a>
       {% endcall %}
     </div>
   </div>