MFA Code Email reformat

[4lb]

Currently, emails send small, bolded code, which is hard to spot and easy to mis-click. Let's provide a bigger code font, separated from the rest, to easily identify and copy. design in figma -> https://www.figma.com/file/uoFcgpOuVWa6g7tvKwB52o/defguard-01?type=design&node-id=6961-3760&mode=design&t=YByQ5UX73Ce469vD-4