* Also fixes an issue where if webp was a downloaded hotlinked
image and then secure + sent in an email, it was not being
redacted because webp was not a supported media format in
FileHelper
* Webp originally removed as an image format in
https://github.com/discourse/discourse/pull/6377
and there was a spec to make sure a .bin webp
file did not get renamed from its type to webp.
However we want to support webp images now to make
sure they are properly redacted if secure media is
on, so change the example in the spec to use tiff,
another banned format, instead
