fix(EntityLoadMultiple): Language param on EntityLoadMultiple data producer shouldn't be multiple (#1025)

Author: juanjol

src/Plugin/GraphQL/DataProducer/Entity/EntityLoadMultiple.php

@@ -30,8 +30,7 @@
  *       multiple = TRUE
  *     ),
  *     "language" = @ContextDefinition("string",
- *       label = @Translation("Entity languages"),
- *       multiple = TRUE,
+ *       label = @Translation("Entity language"),
  *       required = FALSE
  *     ),
  *     "bundles" = @ContextDefinition("string",