Avoid advertising default route for Bridge network

[catfish]

@skye

The metric and pref options are meant to be used for speed: if 2606:4700:4700::1111 isn’t reachable via eth0 then that address shouldn’t be in the routing table for eth0.

It’s reachable if the host can reach it. Because incus managed bridge’s nated:

Which network interface does incusbr0 bind?

The traffic is routed and NATed through the host, so it goes out of whatever network interface is used for your host’s traffic.