fun QrCodeResponses.lineItemsWithDiscountsToDisplay(): List<LineItem>
Used to get a list of line items that include discounts that can be displayed without changing the actual line items list. This keeps things safe for when the order is placed and sent to back end. E.g. The discounts should not be sent up as line items.
Return
A list of line items that also includes the discounts that can be displayed as line items.