Adds null state for ip blocklist

bookwyrm/templates/settings/ip_blocklist/ip_blocklist.html

@@ -43,5 +43,8 @@
     </tr>
     {% endfor %}
 </table>
+{% if not addresses.exists %}
+<p><em>{% trans "No IP addresses currently blocked." %}</em></p>
+{% endif %}
 
 {% endblock %}