POC: Create client-side notices from notices added with wc_add_notice in Checkout block

[opr]

Submission Review Guidelines:

• I have followed the WooCommerce Contributing Guidelines and the WordPress Coding Standards.
• I have checked to ensure there aren't other open Pull Requests for the same update/change.
• I have reviewed my code for security best practices.
• Following the above guidelines will result in quick merges and clear and detailed feedback when appropriate.

Changes proposed in this Pull Request:

• Create a processNotices function - this takes a list of notices in the format returned by wc_get_notices and uses the core/notices data store to add them on the client.
• On error responses in checkout, process the notices.

Note, I have not done this for successful checkouts or other store API actions yet such as changing shipping method, this is only for showing notices added during payment failure.

How to test the changes in this Pull Request:

Using the WooCommerce Testing Instructions Guide, include your detailed testing instructions:

1. Add woocommerce-failed-gateway.zip to your site
2. Try to check out using the failed gateway method
3. See the wc_add_notices notices added when payment fails.

Changelog entry

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Significance

• Patch
• Minor
• Major

Type

• Fix - Fixes an existing bug
• Add - Adds functionality
• Update - Update existing functionality
• Dev - Development related task
• Tweak - A minor adjustment to the codebase
• Performance - Address performance issues
• Enhancement - Improvement to existing functionality

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