[Woo POS] Coupons: Provide coupons to ItemList (happy path)

[iamgabrielma]

Closes: #15416

Description

This PR provides a first step for providing coupons from the service/controller to be rendered in the ItemList view, as well as an initial test suite for the coupons controller.

At the moment we only handle loading the first page of coupons on a happy path (the store has to have coupons). Unhappy paths/pagination/reload have not been handled yet.

Screen.Recording.2025-03-26.at.12.22.33.mov

Testing information

In a POS store, with coupons created:

• Observe that coupons render using the existing CouponRowView and can be added to the cart
• Observe that we cannot create an order only with coupons, at least a product is needed in the cart to checkout
• Observe we can remove coupons from the cart

---

• I have considered if this change warrants user-facing release notes and have added them to RELEASE-NOTES.txt if necessary.

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• The PR is small and has a clear, single focus, or a valid explanation is provided in the description. If needed, please request to split it into smaller PRs.
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📲 You can test the changes from this Pull Request in WooCommerce iOS by scanning the QR code below to install the corresponding build.

	App Name	WooCommerce iOS
	Build Number	pr15417-38b15ce
	Version	22.0
	Bundle ID	com.automattic.alpha.woocommerce
	Commit	38b15ce
	App Center Build	WooCommerce - Prototype Builds #13415

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[staskus]

Thanks! Works well. 👍 And I like that the required changes with the Item list and aggregate model are much smallethanat I anticipated. At least for now.

I found one weird issue, though. It's most likely unrelated to this but could be related to my work on applying coupons or maybe it's some older issue.

Even though I only have one product in a cart, we send request with two products and it fails because such product doesn't exist:

This is a POSProductForRemoval:

I'm not yet sure what is is. I'll check now. [Woo POS] Coupons: Investigate adding invalid coupon and removing it keeps order in error state · Issue #15426 · woocommerce/woocommerce-ios

[staskus]

Nice! Great to see both list and cart functionality integrating so easily 👍