 stackit ske kubeconfig create doesn´t create a kubeconfig when the output is json

Hello!

When you execute the command `stackit ske kubeconfig create ske-001 --expiration 12h -o json` it doesn't create the kubeconfig file.

https://github.com/stackitcloud/stackit-cli/blob/main/internal/cmd/ske/kubeconfig/create/create.go#L134

When you use another output, it does. Should it create the kubeconfig file always?
