Elastic agent field mapping is missing mapping for TBS metrics

[lahsivjar]

https://github.com/elastic/integrations/blob/main/packages/elastic_agent/data_stream/apm_server_metrics/fields/beat-fields.yml is missing mapping for TBS metrics (sampling.tail.*).

Workaround would be to add custom mapping for TBS via custom component template. Something like:

PUT _component_template/metrics-elastic_agent.apm_server@custom
{
  "template": {
    "mappings": {
      "properties": {
        "beat.stats.apm_server.sampling.tail.dynamic_service_groups": {
          "type": "long"
        },
        "beat.stats.apm_server.sampling.tail.events.dropped": {
          "type": "long"
        },
        "beat.stats.apm_server.sampling.tail.events.failed_writes": {
          "type": "long"
        },
        "beat.stats.apm_server.sampling.tail.events.head_unsampled": {
          "type": "long"
        },
        "beat.stats.apm_server.sampling.tail.events.processed": {
          "type": "long"
        },
        "beat.stats.apm_server.sampling.tail.events.sampled": {
          "type": "long"
        },
        "beat.stats.apm_server.sampling.tail.events.stored": {
          "type": "long"
        }
      }
    }
  }
}

[carsonip]

Seems to be a duplicate of #14247