Use default weight label if no field-specific setting is available, as label...

Use default weight label if no field-specific setting is available, as label name is required by tokens module.

Closes #3177299

src/Plugin/Field/FieldType/EntityReferenceHierarchy.php

@@ -47,7 +47,7 @@ class EntityReferenceHierarchy extends EntityReferenceItem {
   public static function propertyDefinitions(FieldStorageDefinitionInterface $field_definition) {
     $properties = parent::propertyDefinitions($field_definition);
     $weight_definition = DataDefinition::create('integer')
-      ->setLabel($field_definition->getSetting('weight_label'));
+      ->setLabel($field_definition->getSetting('weight_label') ?? self::defaultFieldSettings()['weight_label']);
     $weight_definition->addConstraint('Range', ['min' => self::HIERARCHY_MIN_CHILD_WEIGHT]);
     $weight_definition->addConstraint('Range', ['max' => self::HIERARCHY_MAX_CHILD_WEIGHT]);
     $properties['weight'] = $weight_definition;