fix(DataProducer): Support all default field types for Entity Definitions Default Value resolver (#1024)

Author: rthideaway

src/Plugin/GraphQL/DataProducer/EntityDefinition/Fields/DefaultValue.php

@@ -39,6 +39,7 @@ public function resolve(FieldDefinitionInterface $entity_definition_field) {
     if (is_array($default_value)) {
       switch ($entity_definition_field->getType()) {
         case 'list_integer':
+        case 'list_string':
         case 'text_long':
           return $default_value ? $default_value[0]['value'] : NULL;