always show the development server warning #2480
Description
The development server should never be used outside of development. Right now, we show a warning about not using the development server in production if the host is 0.0.0.0 or ::. Flask shows a separate warning if FLASK_ENV=development isn't set. It's not worth doing either of these checks, it's better that users always see this warning, so that they're always aware of the issue.