bug: unverified users get a borked avatar

[Trott]

rich-message.js uses this to calculate the avatar URL in some cases:

'https://github.com/' + message.username + '.png'

However, message.username is intentionally mangled in some cases by friends to be Allegedly so-and-so rather than so-and-so and in those cases, the avatar URL will be wrong and will typically result in a 404.

Would the solution be to use the unmangled username even though the person isn't verified? Or the cat image? Or a new image that is a big question mark or something to show that you can't be sure it's the person it says it is?