[Release 1.25] With tailscale --advertise-address passed to kube-apiserver shows both ipv4 as well as ipv6 address on a ipv6-only setup

[manuelbuil]

Backport: #8020

[est-suse]

##Environment Details
VERSION=v1.25.12+k3s1
COMMIT=11482f9ee1ae58c775ee7c7d55892ef341699ecd

k3s version v1.25.12+k3s-393ac629 (393ac629)
go version go1.20.6

Linux 5.11.0-1022-aws x86_64 GNU/Linux

PRETTY_NAME="Ubuntu 20.04.3 LTS"

Cluster Configuration:

NAME               STATUS   ROLES                       AGE    VERSION
ip-192-168-9-254   Ready    control-plane,etcd,master   4m2s   v1.25.12+k3s-393ac629

config.yaml

=========== k3s config =========== 
write-kubeconfig-mode: 644
debug: true
token: YOUR_TOKEN_HERE

cluster-init: true
cluster-cidr: 2001:cafe:42:0::/56
service-cidr: 2001:cafe:42:1::/112
vpn-auth: "name=tailscale,joinKey=tskey-auth-m0rt@l-W0m3b@t"
node-ip: 2600:cade:iced:eeee:b7a1:6e49:b389:2e60

validation

Install tailscale
Copy config.yaml: sudo mkdir -p /etc/rancher/k3s/ && sudo cp config.yaml /etc/rancher/k3s/config.yaml
Install k3s: curl -sfL https://get.k3s.io |  INSTALL_K3S_COMMIT=11482f9ee1ae58c775ee7c7d55892ef341699ecd sh -
Validate everything is working as expected

NAME               STATUS   ROLES                       AGE    VERSION                 INTERNAL-IP                               EXTERNAL-IP   OS-IMAGE             KERNEL-VERSION    CONTAINER-RUNTIME
ip-192-168-9-254   Ready    control-plane,etcd,master   5m4s   v1.25.12+k3s-393ac629   fd7a:115c:a1e0:ab12:4843:cd96:627b:a968   <none>        Ubuntu 20.04.6 LTS   5.15.0-1036-aws   containerd://1.7.3-k3s1

NAMESPACE     NAME                                      READY   STATUS      RESTARTS   AGE     IP                NODE               NOMINATED NODE   READINESS GATES
kube-system   coredns-8b9777675-fxgf6                   1/1     Running     0          5m3s    2001:cafe:42::4   ip-192-168-9-254   <none>           <none>
kube-system   helm-install-traefik-9zc64                0/1     Completed   1          5m3s    2001:cafe:42::2   ip-192-168-9-254   <none>           <none>
kube-system   helm-install-traefik-crd-v5g6k            0/1     Completed   0          5m3s    2001:cafe:42::3   ip-192-168-9-254   <none>           <none>
kube-system   local-path-provisioner-69dff9496c-zhm4m   1/1     Running     0          5m3s    2001:cafe:42::6   ip-192-168-9-254   <none>           <none>
kube-system   metrics-server-854c559bd-ldw99            1/1     Running     0          5m3s    2001:cafe:42::5   ip-192-168-9-254   <none>           <none>
kube-system   svclb-traefik-dc36a924-fjkk6              2/2     Running     0          4m45s   2001:cafe:42::7   ip-192-168-9-254   <none>           <none>
kube-system   traefik-66fd46ccd-rjhrt                   1/1     Running     0          4m45s   2001:cafe:42::8   ip-192-168-9-254   <none>           <none>