--data-dir gets doubled-up when used as installFlag

[rwos]

a config such as

apiVersion: k0sctl.k0sproject.io/v1beta1
kind: Cluster
metadata:
  name: runway-testing
spec:
  hosts:
  ...
  - role: worker
    installFlags:
      - --data-dir /something

will result in, e.g., a k0sctl apply running commands like

INFO[0010] [ssh] 10.1.2.3:22: installing k0s worker 
DEBU[0010] [ssh] 10.1.2.3:22: executing `sudo -s -- /opt/bin/k0s install worker --data-dir='--data-dir /something' --token-file "/etc/k0s/k0stoken"` 

which doesn't work all that well :)

I'm not 100% certain this would fix it but I think .Get here should be .GetValue - https://github.com/k0sproject/k0sctl/blame/c4e776e70a3d03c8b545845132b2a21392d979fa/pkg/apis/k0sctl.k0sproject.io/v1beta1/cluster/host.go#L71C6-L71C6