use_imagecache_root doesn't work with webp

There is also this issue in the webp issue queue, which is about adding the original extension to the URLs and therefore fix the issue:
🐛 Rendering duplicate images when the original images have the same name but different extension RTBC

When using the webp patch, I had to make a minor change in stage file proxy to include the query parameters in the request. I found that the image token parameter ?itok was needed in the request for the image.

I'm attaching the change I made as a patch.

Don't mind committing that small change if someone can confirm the same.

With such a small change don't mind pushing

Automatically closed - issue fixed for 2 weeks with no activity.