Unassigned task status is not reflected in metrics

[chrisluedtke]

Description

$ curl -s http://localhost:8083/connectors/my_connector/status
{
  "name":"my_connector",
  "connector": {
    "state":"RUNNING",
    "worker_id":"10.7.28.57:8083"
  },
  "tasks":[{"id":0,"state":"UNASSIGNED","worker_id":"10.7.28.57:8083"}],
  "type":"source"
}

$ curl -s localhost:8080 | grep my_connector | grep status
kafka_connect_connector_task_status{connector="my_connector",status="running",task="0",} 1.0

JMX rule:

- pattern: 'kafka.connect<type=connector-task-metrics, connector=(.+), task=(.+)><>status: ([a-z-]+)'
  name: kafka_connect_connector_task_status
  value: "1"
  labels:
    connector: "$1"
    task: "$2"
    status: "$3"
  help: "Kafka Connect JMX Connector task status"
  type: GAUGE

Expected Behavior

Task status metric should report as unassigned.

Reproduce

To force the worker to be unassigned, we set "connect.cosmos.containers.topicmap" to a non-existent container.