Merge branch '3507357-Fix-link-field-issue' into '2.4.x'

Issue #3507357: Fixing error with link field with limited cardinality.

See merge request !111

src/Plugin/GraphQL/DataProducer/FieldProducerPlugin.php

@@ -60,6 +60,8 @@ class FieldProducerPlugin extends DataProducerPluginBase implements FieldProduce
    * {@inheritdoc}
    */
   public function resolveFieldItems(FieldItemListInterface $field, FieldContext $context): array {
+
+    /** @var \Drupal\graphql_compose\Plugin\GraphQLCompose\GraphQLComposeFieldTypeInterface $plugin */
     $plugin = $this->getContextValue('plugin');
 
     if ($plugin instanceof FieldProducerItemsInterface) {
@@ -68,7 +70,10 @@ class FieldProducerPlugin extends DataProducerPluginBase implements FieldProduce
 
     $results = [];
     foreach ($field as $item) {
-      $results[] = $this->resolveFieldItem($item, $context);
+      $result = $this->resolveFieldItem($item, $context);
+      if ($plugin->getPluginId() === 'boolean' || !empty($result)) {
+        $results[] = $result;
+      }
     }
 
     return $results;