Error message
Strict warning: Drupal\Core\Plugin\PluginBase and Drupal\Core\Messenger\MessengerTrait define the same property ($messenger) in the composition of Drupal\webform\Plugin\WebformHandlerBase. This might be incompatible, to improve maintainability consider using accessor methods in traits instead. Class was composed in include() (line 673 of modules/contrib/webform/src/Plugin/WebformHandlerBase.php).