change authorization_modes default value

roles/kubespray-defaults/defaults/main.yaml

@@ -118,5 +118,5 @@ enable_network_policy: false
 ## List of authorization modes that must be configured for
 ## the k8s cluster. Only 'AlwaysAllow','AlwaysDeny', and
 ## 'RBAC' modes are tested.
-authorization_modes: ['AlwaysAllow']
+authorization_modes: []
 rbac_enabled: "{{ 'RBAC' in authorization_modes }}"