Prometheus summaries for ManagedLedger metrics are documented and exposed incorrectly

Describe the bug

Documented as histograms: https://pulsar.apache.org/docs/en/next/reference-metrics/#managedledger-metrics

Exposed as gauges:

# TYPE pulsar_ml_EntrySizeBuckets gauge
pulsar_ml_EntrySizeBuckets{cluster="standalone", namespace="public/functions/persistent", quantile="0.0_128.0"} 0.0 1642717994925
pulsar_ml_EntrySizeBuckets{cluster="standalone", namespace="public/functions/persistent", quantile="1024.0_2048.0"} 0.0 1642717994925
pulsar_ml_EntrySizeBuckets{cluster="standalone", namespace="public/functions/persistent", quantile="102400.0_1232896.0"} 0.0 1642717994925
pulsar_ml_EntrySizeBuckets{cluster="standalone", namespace="public/functions/persistent", quantile="128.0_512.0"} 0.0 1642717994925
pulsar_ml_EntrySizeBuckets{cluster="standalone", namespace="public/functions/persistent", quantile="16384.0_102400.0"} 0.0 1642717994925
pulsar_ml_EntrySizeBuckets{cluster="standalone", namespace="public/functions/persistent", quantile="2048.0_4096.0"} 0.0 1642717994925
pulsar_ml_EntrySizeBuckets{cluster="standalone", namespace="public/functions/persistent", quantile="4096.0_16384.0"} 0.0 1642717994925
pulsar_ml_EntrySizeBuckets{cluster="standalone", namespace="public/functions/persistent", quantile="512.0_1024.0"} 0.0 1642717994925
# TYPE pulsar_ml_EntrySizeBuckets_OVERFLOW gauge
pulsar_ml_EntrySizeBuckets_OVERFLOW{cluster="standalone", namespace="public/functions/persistent"} 0.0 1642717994925
# TYPE pulsar_ml_LedgerAddEntryLatencyBuckets gauge
pulsar_ml_LedgerAddEntryLatencyBuckets{cluster="standalone", namespace="public/functions/persistent", quantile="0.0_0.5"} 0.0 1642717994925
pulsar_ml_LedgerAddEntryLatencyBuckets{cluster="standalone", namespace="public/functions/persistent", quantile="0.5_1.0"} 0.0 1642717994925
pulsar_ml_LedgerAddEntryLatencyBuckets{cluster="standalone", namespace="public/functions/persistent", quantile="1.0_5.0"} 0.0 1642717994925
pulsar_ml_LedgerAddEntryLatencyBuckets{cluster="standalone", namespace="public/functions/persistent", quantile="10.0_20.0"} 0.0 1642717994925
pulsar_ml_LedgerAddEntryLatencyBuckets{cluster="standalone", namespace="public/functions/persistent", quantile="100.0_200.0"} 0.0 1642717994925
pulsar_ml_LedgerAddEntryLatencyBuckets{cluster="standalone", namespace="public/functions/persistent", quantile="20.0_50.0"} 0.0 1642717994925
pulsar_ml_LedgerAddEntryLatencyBuckets{cluster="standalone", namespace="public/functions/persistent", quantile="200.0_1000.0"} 0.0 1642717994925
pulsar_ml_LedgerAddEntryLatencyBuckets{cluster="standalone", namespace="public/functions/persistent", quantile="5.0_10.0"} 0.0 1642717994925
pulsar_ml_LedgerAddEntryLatencyBuckets{cluster="standalone", namespace="public/functions/persistent", quantile="50.0_100.0"} 0.0 1642717994925
# TYPE pulsar_ml_LedgerAddEntryLatencyBuckets_OVERFLOW gauge
pulsar_ml_LedgerAddEntryLatencyBuckets_OVERFLOW{cluster="standalone", namespace="public/functions/persistent"} 0.0 1642717994925
# TYPE pulsar_ml_LedgerSwitchLatencyBuckets gauge
pulsar_ml_LedgerSwitchLatencyBuckets{cluster="standalone", namespace="public/functions/persistent", quantile="0.0_0.5"} 0.0 1642717994925
pulsar_ml_LedgerSwitchLatencyBuckets{cluster="standalone", namespace="public/functions/persistent", quantile="0.5_1.0"} 0.0 1642717994925
pulsar_ml_LedgerSwitchLatencyBuckets{cluster="standalone", namespace="public/functions/persistent", quantile="1.0_5.0"} 0.0 1642717994925
pulsar_ml_LedgerSwitchLatencyBuckets{cluster="standalone", namespace="public/functions/persistent", quantile="10.0_20.0"} 0.0 1642717994925
pulsar_ml_LedgerSwitchLatencyBuckets{cluster="standalone", namespace="public/functions/persistent", quantile="100.0_200.0"} 0.0 1642717994925
pulsar_ml_LedgerSwitchLatencyBuckets{cluster="standalone", namespace="public/functions/persistent", quantile="20.0_50.0"} 0.0 1642717994925
pulsar_ml_LedgerSwitchLatencyBuckets{cluster="standalone", namespace="public/functions/persistent", quantile="200.0_1000.0"} 0.0 1642717994925
pulsar_ml_LedgerSwitchLatencyBuckets{cluster="standalone", namespace="public/functions/persistent", quantile="5.0_10.0"} 0.0 1642717994925
pulsar_ml_LedgerSwitchLatencyBuckets{cluster="standalone", namespace="public/functions/persistent", quantile="50.0_100.0"} 0.0 1642717994925
# TYPE pulsar_ml_LedgerSwitchLatencyBuckets_OVERFLOW gauge
pulsar_ml_LedgerSwitchLatencyBuckets_OVERFLOW{cluster="standalone", namespace="public/functions/persistent"} 0.0 1642717994925

To Reproduce

Steps to reproduce the behavior:

curl -L http://localhost:8080/metrics

version: '3'

services:
  pulsar:
    container_name: pulsar
    image: apachepulsar/pulsar:2.9.1
    command:
    - bash
    - -c
    - >
      bin/apply-config-from-env-with-prefix.py BOOKKEEPER_ conf/bookkeeper.conf &&
      bin/apply-config-from-env-with-prefix.py BROKER_ conf/broker.conf &&
      bin/apply-config-from-env-with-prefix.py STANDALONE_ conf/standalone.conf &&
      exec bin/pulsar standalone
    ports:
    - '6650:6650'
    - '8080:8080'
    environment:
    - BOOKKEEPER_enableStatistics=true
    - BOOKKEEPER_prometheusStatsHttpPort=8080
    - BROKER_exposeTopicLevelMetricsInPrometheus=true
    - BROKER_exposeConsumerLevelMetricsInPrometheus=true
    - BROKER_exposeProducerLevelMetricsInPrometheus=true
    - BROKER_exposeManagedLedgerMetricsInPrometheus=true
    - BROKER_exposeManagedCursorMetricsInPrometheus=true
    - BROKER_exposePublisherStats=true
    - BROKER_exposePreciseBacklogInPrometheus=true
    - BROKER_splitTopicAndPartitionLabelInPrometheus=true
    - STANDALONE_exposeTopicLevelMetricsInPrometheus=true
    - STANDALONE_exposeConsumerLevelMetricsInPrometheus=true
    - STANDALONE_exposeProducerLevelMetricsInPrometheus=true
    - STANDALONE_exposeManagedLedgerMetricsInPrometheus=true
    - STANDALONE_exposeManagedCursorMetricsInPrometheus=true
    - STANDALONE_exposePublisherStats=true
    - STANDALONE_exposePreciseBacklogInPrometheus=true
    - STANDALONE_splitTopicAndPartitionLabelInPrometheus=true

Desktop (please complete the following information):

• OS: Windows 10