Fixing problem that if plugins are installed, but none of the top-lev…

…el ones (the ones shown in the Plugins tab at the top level), you don’t see the “No plugins are currently installed” message when you click on the tab. This was because the code to show that relied on no plugins at all being defined in the system, rather than no top-level ones.

modules/ui/app/views/PluginsTable.html

@@ -10,7 +10,7 @@
             </div>
         </div>
     </div>
-    <div ng-show="!plugins || plugins.length === 0">
+    <div ng-show="!plugins || (plugins | filter:{ pluginType: 'contributeAppLevelFeature' }).length === 0">
         <label>No plugins are currently installed.</label>
     </div>
 </div>