One more great news from our devs 
A bug in the Forms widgets (Subscription Form, Contact Form, Form Builder) has been fixed.
Previously, if the widget was in iframe and the setting was set to redirect to the URL after submit, the redirect occurred inside the iframe.
Now the redirect happens outside the iframe, but in the same tab. Unfortunately, this functionality still does not work on Google Sites due to additional platform restrictions 
Please feel free to share your thoughts regarding this update! Your feedback is extremely important to us 