Issue #3580636: Remove Google branding notice when hiding the badge

This patch removes the automatic Google Privacy Policy / Terms of Service notice that was previously rendered when Hide badge was enabled. The module now only attaches the CSS needed to hide the badge, updates the admin help text, and documents the new behavior in the README so the change is clear for both new and existing users.

See:

• https://security.googlecloudcommunity.com/community-blog-42/switching-google-s-role-with-recaptcha-from-data-controller-to-data-processor-6646
• https://docs.cloud.google.com/recaptcha/docs/faq#hiding-the-badge

Closes #3580636