fix(previews): Handle Faust frontend URL-HWP Previews iframe conflict

[ahuseyn]

@colinmurphy we already remove the previews link replacement functionality of Faust by enabling the HWP Previews with #240. The iframe issue here is related to "redirect all to frontend" feature of Faust which is not connected to the previews. That's why I think we shouldn't do anything about it. If users want to use iframe with Faust, they can disable the redirect functionality by removing frontend url from the settings, and I'll document this fix.

Wouldn't removing the front-end URL from Faust config also break link rewrites? Not sure that's a viable fix for this issue.

Originally posted by @moonmeister in #233

As per this discussion, a new way of handling the iframe conflict should be presented. new solution should only target the preview links without disturbing the other Faust redirects. This hook in Faust could be modified or a new hook could be added there to handle this case.