DLedger mode metrics will display the old master data

[maixiaohai]

Describe the bug
When restart cluster which deployed on DLedger mode, the master may change.But the broker tps metrics will always show the old one.

To Reproduce
1.restart cluster and the master broker machine change.
2.the exporter service not restart.

Expected behavior
only new metrics data show, or the old data change to 0.

Screenshots
tps dashboard

some exporter data:

rocketmq_broker_tps{cluster="c3cloudsrv-common-rocketmq",brokerIP="Amachine",broker="c3cloudsrv-common-rocketmq-raft0",} 33441.97
rocketmq_broker_tps{cluster="c3cloudsrv-common-rocketmq",brokerIP="Bmachine",broker="c3cloudsrv-common-rocketmq-raft1",} 13892.3
rocketmq_broker_tps{cluster="c3cloudsrv-common-rocketmq",brokerIP="",broker="c3cloudsrv-common-rocketmq-raft1",} 0.0
rocketmq_broker_tps{cluster="c3cloudsrv-common-rocketmq",brokerIP="Cmachine",broker="c3cloudsrv-common-rocketmq-raft1",} 0.0
rocketmq_broker_tps{cluster="c3cloudsrv-common-rocketmq",brokerIP="Dmachine",broker="c3cloudsrv-common-rocketmq-raft1",} 12083.87
rocketmq_broker_tps{cluster="c3cloudsrv-common-rocketmq",brokerIP="Emachine",broker="c3cloudsrv-common-rocketmq-raft0",} 12083.2
rocketmq_broker_tps{cluster="c3cloudsrv-common-rocketmq",brokerIP="Fmachine",broker="c3cloudsrv-common-rocketmq-raft0",} 12270.9

there is only two master in the cluster, but the metrics is more than 2.

• rocketmq version 4.7.0

• exporter version 0.0.2

[maixiaohai]

@francisoliverlee May I submit a pr to fix this?

[maixiaohai]

After fix the broker stats always return 2 master data

rocketmq_broker_tps{cluster="c3cloudsrv-common-rocketmq",brokerIP="A",broker="c3cloudsrv-common-rocketmq-raft1",} 11848.72
rocketmq_broker_tps{cluster="c3cloudsrv-common-rocketmq",brokerIP="B",broker="c3cloudsrv-common-rocketmq-raft0",} 11847.95
rocketmq_broker_qps{cluster="c3cloudsrv-common-rocketmq",brokerIP="A",broker="c3cloudsrv-common-rocketmq-raft1",} 23774.55
rocketmq_broker_qps{cluster="c3cloudsrv-common-rocketmq",brokerIP="B",broker="c3cloudsrv-common-rocketmq-raft0",} 23340.07