UI: Fix status menu bug (#11213)

* change null to empty string

* add changelog

* add conditional

* amend to set path

changelog/11213.txt

@@ -0,0 +1,3 @@
+```release-note:bug
+ui: Fix status menu no showing on login
+```

ui/app/services/namespace.js

@@ -8,7 +8,7 @@ export default Service.extend({
   auth: service(),
   userRootNamespace: alias('auth.authData.userRootNamespace'),
   //populated by the query param on the cluster route
-  path: null,
+  path: '',
   // list of namespaces available to the current user under the
   // current namespace
   accessibleNamespaces: null,
@@ -16,6 +16,10 @@ export default Service.extend({
   inRootNamespace: equal('path', ROOT_NAMESPACE),
 
   setNamespace(path) {
+    if (!path) {
+      this.set('path', '');
+      return;
+    }
     this.set('path', path);
   },