Dropdown component.jsx update

On mobile if you clicked on a user or your own user to set their status, the tethered modal would keep it's z-index, which would prevent the user from interacting with anything because the tethered modal would overlap the whole site.

bigbluebutton-html5/imports/ui/components/dropdown/component.jsx

@@ -161,7 +161,7 @@ class Dropdown extends Component {
       if (parentElement) parentElement.focus();
     }
 
-    if (keepOpen !== null) return;
+    if (keepOpen !== false) return;
     this.handleHide();
   }