Fatal error: Uncaught Error: Class "Drupal\layout_builder\Form\ConfigureBlockFormBase" not found in /home/www/drupal8/test/core/modules/layout_builder/src/Form/AddBlockForm.php:14 Stack trace: #0 {main} thrown in /home/www/drupal8/test/core/modules/layout_builder/src/Form/AddBlockForm.php on line 14