ea55f96310
When a user deletes the last cluster/user/context from their kubeconfig via 'kubectl delete-[cluster|user|context] command, kubectx sets the relevant field in kubeconfig to 'null'. This was breaking our conversion logic that was assuming that the field is either non-existant or is an array. Updates tailscale/corp#18320 Signed-off-by: Irbe Krumina <irbe@tailscale.com>