fix(client): add loader to default layouts (#48830)

client/src/components/layouts/default.tsx

@@ -34,6 +34,7 @@ import SignoutModal from '../signout-modal';
 import Footer from '../Footer';
 import Header from '../Header';
 import OfflineWarning from '../OfflineWarning';
+import { Loader } from '../helpers';
 
 // preload common fonts
 import './fonts.css';
@@ -155,6 +156,10 @@ class DefaultLayout extends Component<DefaultLayoutProps> {
 
     const useSystemTheme = fetchState.complete && isSignedIn === false;
 
+    if (fetchState.pending) {
+      return <Loader fullScreen={true} />;
+    }
+
     return (
       <div className='page-wrapper'>
         <Helmet