WebUI: Remove IRC in about page

This follows the GUI change in 65a30bab3f.

src/webui/www/private/views/about.html

@@ -6,7 +6,6 @@
     <p>QBT_TR(Home Page:)QBT_TR[CONTEXT=AboutDialog] <a target="_blank" href="https://www.qbittorrent.org"> https://www.qbittorrent.org</a></p>
     <p>QBT_TR(Bug Tracker:)QBT_TR[CONTEXT=AboutDialog] <a target="_blank" href="http://bugs.qbittorrent.org"> http://bugs.qbittorrent.org</a></p>
     <p>QBT_TR(Forum:)QBT_TR[CONTEXT=AboutDialog] <a target="_blank" href="http://forum.qbittorrent.org"> http://forum.qbittorrent.org</a></p>
-    <p>QBT_TR(IRC: #qbittorrent on Freenode)QBT_TR[CONTEXT=HttpServer]</p>
 </div>
 
 <div id="aboutAuthorContent" class="aboutTabContent invisible">