Fatal error: Uncaught Error: Class "Drupal\Component\Plugin\Definition\PluginDefinition" not found in /home/www/drupal8/test/core/modules/layout_builder/src/SectionStorage/SectionStorageDefinition.php:15 Stack trace: #0 {main} thrown in /home/www/drupal8/test/core/modules/layout_builder/src/SectionStorage/SectionStorageDefinition.php on line 15