Add cluster name to account replica count stats

[ColinSullivan1]

looks like doesn’t have cluster tag in nats_core_account_jetstream_replica_count metrics for _, streamStat := range stat.jetstreamStreams { ch <- newGaugeMetric(sc.descs.accJetstreamConsumerCount, streamStat.consumerCount, append(id, streamStat.streamName)) ch <- newGaugeMetric(sc.descs.accJetstreamReplicaCount, streamStat.replicaCount, append(id, streamStat.streamName)) }