feat(my-account): reCAPTCHA check on add payment method

[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 a reCAPTCHA check to the form to add payment methods in My Account.

How to test the changes in this Pull Request:

We'll want to test with both reCAPTCHA v2 and v3.

1. Enable reCAPTCHA v2 in Newspack > Connections and check out this branch.
2. At this line, add error_log( print_r( $captcha_verify, true ) ); so we can confirm that we're verifying with the reCAPTCHA service after form submit.
3. Register a new reader account, log in, and verify as needed to view My Account.
4. Visit <site URL>/my-account/add-payment-method/ and add a payment method.
5. (when testing v2 only) Confirm that you get a v2 widget challenge when you click the "Add payment method" submit button.
6. After submitting the form, confirm that the verification result is logged to debug.log (after adding the error_log in step 2).
7. To test a rejection, add return new \WP_Error( 'newspack_test_error', 'Test error message' ); at this line.
8. Repeat the "Add payment method" form submission and confirm that the submission is rejected with your test error message (note that the message might disappear after a second, but this seems to be a WooCommerce behavior and not related to this PR). Visit <site URL>/my-account/payment-methods and confirm that a new payment method was NOT saved.
9. Repeat all testing steps with reCAPTCHA v3.

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?

---

• To see the specific tasks where the Asana app for GitHub is being used, see below:
  • https://app.asana.com/0/0/1209016655921587

[matticbot]

🎉 This PR is included in version 5.11.0 🎉

The release is available on GitHub release

Your semantic-release bot 📦🚀