AAAA records not resolved in containers with `network.address=true` on dual-stack macOS host

### Description

when using `network.address=true vmType=vz` (and getting vzNAT network), the containers and the colima vm are able to reach dual-stack networks. however, DNS still does not resolve IPv6 records.

initially I've thought that the issue was caused by `hostResolver.ipv6` not being set – but turns out I was wrong. leaving my original assumption for history, see https://github.com/abiosoft/colima/issues/1275#issuecomment-2682333806 for correct info.

original issue description -- was incorrect

currently hostResolver.ipv6 is never set:
https://github.com/abiosoft/colima/blob/e79883bde6581b8ab0db8d0c63103cf4b1e89f8a/environment/vm/lima/yaml.go#L72-L81

however, it's possible to get a somewhat working IPv6 network in container with:
```
network:
address: true

docker:
fixed-cidr-v6: SOME-RANDOM-ULA-CIDR::/48
ipv6: true
```

but the DNS won't resolve AAAA records since `hostResolver.ipv6` property is not set in the lima config.

would be great to allow setting it from the network settings, or to even set it to true automatically if `network.address` is set to true in Colima spec.