Generates a prescription discount coupon optimized for printing, returned as a PNG image URL.

Typical workflow:

1. Call a pricing endpoint to get price quotes
2. User selects a partner and price
3. Call this endpoint with the selected partner name, NDC, quantity, and price
4. Display or download printCouponURL for the user to print
5. The cardDetails fields (BIN, group, PCN, member number) can be read aloud or entered
   manually at a pharmacy that cannot scan the coupon image

Use PBAClientName (V1 pricing) or PricingPartner (V2 pricing) as pricingPartner.

Differences from /marketplace/v1/coupon/view:

• No locale field — print coupons are English only
• Returns printCouponURL (not couponURL) — image sized for print dimensions