Fixed rendering error on /start when not logged in (#30023)

app/javascript/mastodon/features/onboarding/index.jsx

@@ -16,6 +16,7 @@ import EditNoteIcon from '@/material-icons/400-24px/edit_note.svg?react';
 import PersonAddIcon from '@/material-icons/400-24px/person_add.svg?react';
 import { focusCompose } from 'mastodon/actions/compose';
 import { Icon }  from 'mastodon/components/icon';
+import { NotSignedInIndicator } from 'mastodon/components/not_signed_in_indicator';
 import Column from 'mastodon/features/ui/components/column';
 import { me } from 'mastodon/initial_state';
 import { useAppSelector } from 'mastodon/store';
@@ -42,6 +43,7 @@ const Onboarding = () => {
 
   return (
     <Column>
+      {account ? (
         <Switch>
           <Route path='/start' exact>
             <div className='scrollable privacy-policy'>
@@ -78,6 +80,7 @@ const Onboarding = () => {
           <Route path='/start/follows' component={Follows} />
           <Route path='/start/share' component={Share} />
         </Switch>
+      ) : <NotSignedInIndicator />}
 
       <Helmet>
         <meta name='robots' content='noindex' />