fix (ras-acc): add styles for terms and conditions

[laurelfulford]

All Submissions:

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

Changes proposed in this Pull Request:

This PR adds some styles for WooCommerce's built in terms and conditions checkbox, which appears on the second screen of the modal checkout.

See: 1207817176293825-as-1208279455320432

How to test the changes in this Pull Request:

1. Create a page and title it "Terms and Conditions" or something similar. Give it some text content.
2. Under WP Admin > WooCommerce > Advanced, under the Page Settings header, use the Terms and conditions dropdown to find your page:

3. Run through a checkout; note the appearance of the Terms and Conditions checkbox at the bottom of the second screen.

4. Click the Terms and Conditions text to open the terms details and note the appearance.

5. Apply this PR and run npm run build.
6. Repeat steps 3 and 4 and confirm that the Terms checkbox and details look better:

Other information:

• [x] 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?

[laurelfulford]

@kevinzweerink gave a thumbs up in the Asana task, so I'm going to remove the Needs Design Review label.

[laurelfulford]

Thanks @adekbadek!