[BUG] Guest order and PromotionEligibilityChecker

@umpirsky Right now guest order will never pass the checker

https://github.com/Sylius/Sylius/blob/025f903aa89dfb4108f42e50277cd7c62b850be2/src/Sylius/Component/Core/Promotion/Checker/PromotionEligibilityChecker.php#L52-L59