Ability to Change the hasFixedSyrveCardDiscounts Parameter

Starting from API V8, we renamed the hasSyrveCardDiscounts parameter of the CreateOrder, CreateDeliveryOrder methods to hasFixedSyrveCardDiscounts, and also added the ability to change it.

To do this, a new method SetOrderHasFixedSyrveCardDiscounts has been added to the API, which allows you to change the value of HasFixedDiscounts for both delivery and regular orders.