Add an option to remove the "you are opening a codesandbox preview" warning on the preview page

[anton-series]

Please add the ability to remove the warning screen that appears before the preview, or mention in the docs that the screen is non-removable.

We are showing temporary apps running in the sandbox for our users and they are confused when they see this screen.

[CompuIves]

Hey! Yes, this is an important thing we should fix asap. I expect we'll be able to get rid of this in first week of January.

For an intermediate solution, we don't show this interstitial for pro users (with the idea that users who create phishing pages are not pro).