DEV: Update to Font Awesome 6 icon names

Author: tyb-talks

admin/assets/javascripts/discourse/templates/admin/plugins-house-ads.hbs

@@ -12,7 +12,7 @@
           <span>{{i18n "admin.adplugin.house_ads.new"}}</span>
         </LinkTo>
         <LinkTo @route="adminPlugins.houseAds.index" class="btn btn-default">
-          {{d-icon "cog"}}
+          {{d-icon "gear"}}
           <span>{{i18n "admin.adplugin.house_ads.settings"}}</span>
         </LinkTo>
       </div>