[bug]: externalhosts does not advertize IPv4+IPv6 domain

Background

Describe your issue here.

Your environment

• version of lnd 0.17.3
• which operating system (uname -a on *Nix) ubuntu 20.04
• version of btcd, bitcoind, or other backend
• any other relevant environment details

Steps to reproduce

I run a node that I want accessible via clearnet IPv4, IPv6 and Tor. I have a domain lightning.foo.com that has both A and AAAA DNS records. When I set this in lnd.conf

externalhosts=lightning.foo.com

The node advertises only IPv4 and Tor (as checked via getinfo)

Expected behaviour

If a domain resolves to both IPv4 and IPv6 lnd should advertise both protocols

Actual behaviour

The node favors one of the protocols. I guess this code does the resolve on the first interface https://github.com/lightningnetwork/lnd/blob/613bfc07fb664086e78e8c58c9e1c8785e4656d9/server.go#L1644