I’m not expert in terms of hosting and web servers, but i can give you an idea:
Maybe there is a chance the reviewer is using a custom hosts.txt file similar to this: https://www.siteground.com/kb/how_to_use_the_hosts_file/ to resolve envato.test in his local environment (it is pretty common to add 127.0.0.1 and resolve a custom url).
You can try to fix that changing the way how is importing curl (not sure if can be done with a file path instead of url path) or what i do to avoid any kind of import error, upload that plugin into your private server and change the url, e.g http://example.com/repo/myplugins/visual_composer.zip
You can add some security parameters to avoid anyone can download you files (or being indexed) but that should do the work.
Hope my comment may help you.