[Backport to release/11.0] Store API: enforce coupon global usage limit when paying for an existing order - #67549

Testing Guidelines

Hi @senadir @LiamSarsfield ,

Apart from reviewing the code changes, please make sure to review the testing instructions (Guide) and verify that relevant tests (E2E, Unit, Integration, etc.) have been added or updated as needed.

Reminder: PR reviewers are required to document testing performed. This includes:

• 🖼️ Screenshots or screen recordings.
• 📝 List of functionality tested / steps followed.
• 🌐 Site details (environment attributes such as hosting type, plugins, theme, store size, store age, and relevant settings).
• 🔍 Any analysis performed, such as assessing potential impacts on environment attributes and other plugins, conducting performance profiling, or using LLM/AI-based analysis.

⚠️ Within the testing details you provide, please ensure that no sensitive information (such as API keys, passwords, user data, etc.) is included in this public issue.

Test using WordPress Playground

The changes in this pull request can be previewed and tested using a WordPress Playground instance.
WordPress Playground is an experimental project that creates a full WordPress instance entirely within the browser.

Test this pull request with WordPress Playground.

Note that this URL is valid for 30 days from when this comment was last updated. You can update it by closing/reopening the PR or pushing a commit that changes plugin code.

⚠️ API Documentation Reminder

Hi @woocommercebot! Your PR contains REST API changes. Please consider updating the REST API documentation if your changes affect the public API.

Changed API files:

plugins/woocommerce/src/StoreApi/Utilities/OrderController.php