Fatal error: Uncaught Error: Interface 'Drupal\Core\Plugin\PluginFormInterface' not found in /var/www/html/tmp/contrib/flag/src/ActionLink/ActionLinkTypePluginInterface.php:13 Stack trace: #0 {main} thrown in /var/www/html/tmp/contrib/flag/src/ActionLink/ActionLinkTypePluginInterface.php on line 13