[WSL2] cidata scripts incorrectly set proxy variables

[arixmkii]

Description

When proxy is set to localhost like

set ftp_proxy=http://localhost:2121

During machine creation this will be replaced with a predefined SlirpGateway, which is not a thing for WSL2 template

[lima@ ~]$ ip route
default via 172.31.176.1 dev eth0 proto kernel
172.31.176.0/20 dev eth0 proto kernel scope link src 172.31.181.242
[lima@ ~]$ env | grep -i proxy
ftp_proxy=http://192.168.5.2:2121
FTP_PROXY=http://192.168.5.2:2121

This is probably result in some programs failing to work and also breaks integration test.

[arixmkii]

This should also take into account mirrored networking mode, where localhost would be invalid gateway as VM and host share the same network address.