Fixed the field entity ui issues

Closes #3511454

src/Plugin/Group/RelationHandlerDefault/OperationProvider.php

@@ -7,6 +7,7 @@ use Drupal\Core\Extension\ModuleHandlerInterface;
 use Drupal\Core\Session\AccountProxyInterface;
 use Drupal\Core\StringTranslation\TranslationInterface;
 use Drupal\Core\Url;
+use Drupal\field_ui\Hook\FieldUiHooks;
 use Drupal\group\Entity\GroupInterface;
 use Drupal\group\Entity\GroupTypeInterface;
 use Drupal\group\Plugin\Group\Relation\GroupRelationTypeManagerInterface;
@@ -71,11 +72,19 @@ class OperationProvider implements OperationProviderInterface {
         ];
       }
 
-      // This could be in its own decorator, but then it would live in a module
-      // of its own purely for field_ui support. So let's keep it here.
+      // Use a safer alternative to field_ui_entity_operation()
       if ($this->moduleHandler->moduleExists('field_ui')) {
         $relationship_type = $this->entityTypeManager()->getStorage('group_relationship_type')->load($relationship_type_id);
-        $operations += field_ui_entity_operation($relationship_type);
+        if ($relationship_type) {
+          // Try using the right method for adding the Field UI entity operations.
+          $operations += match (TRUE) {
+            // Drupal version >= 11.1.x.
+            method_exists(FieldUiHooks::class, 'entityOperation') => (new FieldUiHooks())->entityOperation($relationship_type),
+            // Drupal version < 11.1.x.
+            function_exists('field_ui_entity_operation') => field_ui_entity_operation($relationship_type),
+            default => [],
+          };
+        }
       }
     }
     elseif ($ui_allowed) {