Render A4A payment notice CTAs

[cleacos]

Part of A4A-2583

Proposed Changes

This PR updates the A4A payment-risk banner to render CTA labels and URLs from the backend payment_notice payload.

• Add primary and secondary CTA fields to the A4A payment notice type.
• Use backend-provided CTA labels and links in the banner.
• Render a secondary CTA only when the backend provides one.
• Keep legacy action_label and action_url as primary CTA fallbacks.
• Avoid showing the old update-payment-method fallback for notices where the current user cannot manage the payment method.
• Keep the existing feature flag and title/content fallback behavior.

Why are these changes being made?

The WPCOM agency endpoint now returns contextual payment-risk notices for agency-owned purchases and referred client purchases. Calypso needs to display the matching CTA copy and destination so agencies know whether to update their own payment method or send instructions to a client.

Testing Instructions

• Check the code changes.
• Open the A4A overview page with the a4a-payment-risk-notice-banner flag enabled and a payment notice payload.
• Verify agency-owned notices show the update-payment-method CTA and billing FAQ CTA.
• Verify referral-agency notices show only the client-instructions CTA.

Pre-merge Checklist

• Has the general commit checklist been followed? (PCYsg-hS-p2)
• Have you written new tests for your changes?
• Have you tested the feature in Simple (P9HQHe-k8-p2), Atomic (P9HQHe-jW-p2), and self-hosted Jetpack sites (PCYsg-g6b-p2)?
• Have you checked for TypeScript, React or other console errors?
• For UI changes, have you tested the affected components in dark mode?
• Have you tested accessibility for your changes? Ensure the feature remains usable with various user agents (e.g., browsers), interfaces (e.g., keyboard navigation), and assistive technologies (e.g., screen readers) (PCYsg-S3g-p2).
• Have you used memoizing on expensive computations? More info in Memoizing with create-selector and Using memoizing selectors and Our Approach to Data
• Have we added the "[Status] String Freeze" label as soon as any new strings were ready for translation (p4TIVU-5Jq-p2)?
  • For UI changes, have we tested the change in various languages (for example, ES, PT, FR, or DE)? The length of text and words vary significantly between languages.
• For changes affecting Jetpack: Have we added the "[Status] Needs Privacy Updates" label if this pull request changes what data or activity we track or use (p4TIVU-aUh-p2)?

[github-actions]

Calypso Live (direct link)

https://calypso.live?image=registry.a8c.com/calypso/app:build-184266

Jetpack Cloud Live (direct link)

https://calypso.live?image=registry.a8c.com/calypso/app:build-184266&env=jetpack

Automattic for Agencies Live (direct link)

https://calypso.live?image=registry.a8c.com/calypso/app:build-184266&env=a8c-for-agencies

Dashboard Live (dotcom) (direct link)

https://calypso.live?image=registry.a8c.com/calypso/app:build-184266&env=dashboard

Dashboard Live (A4A) (direct link)

https://calypso.live?image=registry.a8c.com/calypso/app:build-184266&env=dashboard-a4a

[matticbot]

This PR modifies the release build for the following Calypso Apps:

For info about this notification, see here: PCYsg-OT6-p2

• help-center
• notifications
• wpcom-block-editor

To test WordPress.com changes, run install-plugin.sh $pluginSlug a4a/payment-notice-context-messages-calypso on your sandbox.