[BUG] Relay Header has fixed width span inside header table, doesn't wrap properly on small screens

[jedfonner]

On line 72 of emails/templates/emails/wrapped_email.html, the .forwarded-from-email class hardcodes a width of 500px

On small screens, this causes the header to scroll off the side of the screen. On mobile devices that resize the email to fit the width, it causes the body of the email to be very small.

The comment says /* this deals with long email addresses */ but I recommend using something like width:fit-content (which is decently supported by email clients) or just picking a size that will work better on phones, such as 360px (or better yet, use a @media query to dynamically change the width based on form factor).