feat: add support for mdns multi-interface

[zh522130]

My testing environment is as follows:

Device A turns on a Wi-Fi hotspot (Device A cannot access the internet) and runs an iroh program with mDNS discovery enabled.

Device B connects to A via Wi-Fi, but Device B cannot discover Device A through mDNS.

I tested swarm-discovery 0.4.0 and encountered the same issue.

I tested the multi-interface branch, Device B was able to discover Device A normally. Therefore, this issue requires updating iroh after the branch is merged.