wireguard mode: binding to both IPv4 and IPv6 by default does not work as expected

[decathorpe]

This issue was previously reported here:
decathorpe/mitmproxy_wireguard#23

The same potentially problematic code is still present in mitmproxy_rs:
https://github.com/mitmproxy/mitmproxy_rs/blob/main/src/packet_sources/wireguard.rs#L88-L96

I'm opening a ticket here since mitmproxy_rs does not seem to have an open issue tracker.

[mhils]

For UDP mode, we have fixed this as follows: https://github.com/mitmproxy/mitmproxy/blob/10.2.2/mitmproxy/proxy/mode_servers.py#L294-L310

We should probably do the same for WireGuard :)