TF Show exposes cluster-admin token as non sensitive value

[jdftapi]

We use terraform show to show the current TF state in our CI pipelines. MetaKube Cluster objects expose the default user token in the kube_config field.

As this token/the kubeconfig enables cluster-admin settings, we would prefer if the kubeconfig was handled like a sensitive value and the output would not show in TF show, similar to the project_id field.