[Woo POS] Coupons: Checkout - Error Handling (Designer UI)

[staskus]

Designs: https://peacockp2.wordpress.com/2025/03/31/pos-coupons-feature-design-v1/

• Error State and Multiple Coupons.
• • Show ‘Remove Coupons’ CTA
  • Show ‘Coupon Not Applied’ on all the coupons.

The flow from designs depends on the backend changes and it still wouldn't be robust due to checking for coupon code with the error message. Let's simplify this for now.

[dangermattic]

🚫 Please add a type label (e.g. type: enhancement) and a feature label (e.g. feature: stats) to this issue.