Support for `:Files` over a local vim edit of a remote file over scp

- [x] I have fzf 0.30.0 or above
- [x] I have read through https://github.com/junegunn/fzf.vim/blob/master/README.md
- [x] I have read through https://github.com/junegunn/fzf/blob/master/README-VIM.md
- [x] I have read through the manual page of fzf (`man fzf`)
- [x] I have searched through the existing issues

Support for `:Files` over a local vim edit of a remote file is currently not working.

I'm using the following `~/.ssh/config' :
```
Host *
ControlPath /tmp/ssh-socket-%r@%h-%p
```
Then starting a ssh multiplexing sessinon:
```bash
$ ssh -MNv user@host
```
And in another terminal, open a remote file over the multiplexed ssh session:
```bash
$ vim scp://user@host/myfile.md
```

This enables me to run vim locally instead on the remote, and automatically have all my plugins instead of installing them on each remote host.

However, if I run `:Files`, the list is populated with the files from the local folder.

Conversely, when I run `:Vex`, the files listed are the ones from the remote.

Is this a missing feature in `fzf.vim` or a configuration I could do on my side?