Remove the kubernetes set on enable_firewall (vultr#531)

This field is only present on the create route

vultr/resource_vultr_kubernetes.go

@@ -236,9 +236,6 @@ You must set the default tag on one node pool before importing.`,
 	if err := d.Set("ha_controlplanes", vke.HAControlPlanes); err != nil {
 		return diag.Errorf("unable to set resource kubernetes `ha_controlplanes` read value: %v", err)
 	}
-	if err := d.Set("enable_firewall", nil); err != nil {
-		return diag.Errorf("unable to unset resource kubernetes `enable_firewall` read value: %v", err)
-	}
 	if err := d.Set("firewall_group_id", vke.FirewallGroupID); err != nil {
 		return diag.Errorf("unable to set resource kubernetes `firewall_group_id` read value: %v", err)
 	}