TaiYi

fix: ignored rocketmq_group_get_latency_by_storetime for boardcast consumer

1

Get consumer latency only when messageModel is clustering，otherwise boardcast consumer's latency is too large which cause trouble. Detail in issue.

The metric of rocketmq_group_get_latency_by_storetime should ignored for boardcast consumer

1

As boardcast consumer's offset would not report to broker，so calculate the latency according to the offset of the consumer's and broker's is meaningless for broadcast consumers.