Docs failing to serve the lite IFrames

[martinRenou]

Description

https://jupyterlite-sphinx.readthedocs.io/ is currently showing 404 issues that were not happening on the latest PR https://jupyterlite-sphinx--32.org.readthedocs.build/en/32/

There might be an issue with the src of the IFrames but I have troubles understanding what is the issue exactly.

cc. @psychemedia

[psychemedia]

I note you had changed iframe paths in 9548740 ?