'#tree' => TRUE,
];
+ $form['field_layouts']['settings_wrapper']['icon'] = $layout_plugin->getPluginDefinition()->getIcon();
+
if ($layout_plugin instanceof PluginFormInterface) {
$form['field_layouts']['settings_wrapper']['layout_settings'] = [];
$subform_state = SubformState::createForSubform($form['field_layouts']['settings_wrapper']['layout_settings'], $form, $form_state);