Invalid Error Displays Twice.r=rbillings

Used the style="display:none" initially in the DOM if the messages.tags contains "warning" and "modal".
This is a good idea @skjindal93, but we shouldn't be adding explicit styles into the html template, we should be using a css class instead. See if there is already one that is applicable in https://github.com/mozilla/oneanddone/blob/master/oneanddone/base/static/css/one-and-done.less and if not add one there and use it here.