fix(recaptcha): log verification responses and errors

[dkoo]

All Submissions:

• Have you followed the Newspack Contributing guideline?
• Does your code follow the WordPress' coding standards and VIP Go coding standards?
• Have you checked to ensure there aren't other open Pull Requests for the same update/change?

Changes proposed in this Pull Request:

Adds some debug and error logging when a site makes a verification request (assessment) to the reCAPTCHA API. This will let us better estimate reCAPTCHA usage across the Newspack platform.

This only logs when the request is sent server-side—it doesn't separately log requests sent directly to the reCAPTCHA API via JS when using v2. This is because we double-verify captcha tokens fetched via JS with a server-side request to avoid unverified direct POST requests. Since the server-side requests are simply verifying the captcha token that was fetched on the front-end (and not fetching a new token to assess the validity of the request), I don't believe this counts as a separate assessment—but it's unclear from Google's documentation exactly how they count assessments on their end.

Closes NPPD-900.

How to test the changes in this Pull Request:

1. Check out this branch.
2. In Newspack > Settings, enable reCAPTCHA v2 and add credentials, if necessary
3. As a reader, perform actions across the site that are protected by reCAPTCHA:

• Reader account registration via the Sign In modal or registration block
• Newsletter signup via the Newsletter Subscription block
• Checkout payment attempts via the modal checkout and regular Woo checkout

4. Confirm that for each action, the request is logged via newspack_log with info about the request: reCAPTCHA version (v2_invisible or v3), score (if using v3), timestamp of the challenge completion (if using v2), success status, hostname, etc.
5. Switch to using reCAPTCHA v3 and repeat the protected actions on the front-end. Confirm that the requests are logged with v3-appropriate data.

Other information:

• Have you added an explanation of what your changes do and why you'd like us to include them?
• Have you written new tests for your changes, as applicable?
• Have you successfully ran tests with your changes locally?

[matticbot]

🎉 This PR is included in version 6.27.3 🎉

The release is available on GitHub release

Your semantic-release bot 📦🚀

[matticbot]

🎉 This PR is included in version 6.28.0-alpha.3 🎉

The release is available on GitHub release

Your semantic-release bot 📦🚀