Don't clear the new user's registration form when viewing terms page

[wdoug]

Perhaps the simplest solution for this is to open the terms in a new tab with target="_blank" and rel="noopener noreferrer" attributes on the link. On the other hand, the preferable UX solution is probably to open the terms in a modal or something. If we want to do that we should consider pulling a react one if from a library e.g. http://www.material-ui.com/#/components/dialog