Use LoadBalancerName field of CLB task when attaching CLBs to existing ASGs

This shouldn't have a functional change, just improving consistency with how we attach CLBs to ASGs being created

upup/pkg/fi/cloudup/awstasks/autoscalinggroup.go

@@ -717,7 +717,7 @@ func (e *AutoscalingGroup) AutoscalingLoadBalancers() []*string {
 	var list []*string
 
 	for _, v := range e.LoadBalancers {
-		list = append(list, v.Name)
+		list = append(list, v.LoadBalancerName)
 	}
 
 	return list