fix: app.tsx and revert it to the original state

src/App.tsx

@@ -9,7 +9,6 @@ import {
 import './App.css';
 import { useTranslation } from 'react-i18next';
 import { LanguageManager } from './components/LanguageManager';
-import { UserCompletionForm } from './features/authentication/components/UserCompletionForm';
 
 function App() {
   const { t } = useTranslation();
@@ -19,7 +18,6 @@ function App() {
     <>
       <CssBaseline />
       <LanguageManager />
-      <UserCompletionForm />
       <div style={{ padding: '16px' }}>
         <Typography variant="h3">{t('helloWorld')}</Typography>
         <Box