fix(my-account): safe content argument to skip sanitization

[miguelpeixe]

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:

NPPD-989

Modal content from Woo template tags may include markup from hooks. This markup can be script and style tags, which should be allowed.

This PR introduces a content_is_safe flag so the modal content renders without sanitization.

How to test the changes in this Pull Request:

1. While on trunk, make sure you have My Account v1 enabled
2. Configure and enable reCAPTCHA (Newspack -> Settings -> Connections)
3. As a reader, add a new payment method (My Account -> Payment information)
4. Confirm the reCAPTCHA script tag is sanitized and its contents printed:

5. Checkout this branch, refresh the page, and confirm the script is preserved in the markup

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?