List escalation levels for an Escalation Policy

curl --request GET \
  --url https://api.rootly.com/v1/escalation_policies/{escalation_policy_id}/escalation_levels \
  --header 'Authorization: Bearer <token>'

{
  "data": [
    {
      "id": "<string>",
      "attributes": {
        "escalation_policy_id": "<string>",
        "delay": 123,
        "position": 123,
        "notification_target_params": [
          {
            "id": "<string>"
          }
        ],
        "escalation_policy_path_id": "<string>",
        "paging_strategy_configuration_strategy": "default",
        "paging_strategy_configuration_schedule_strategy": "on_call_only",
        "created_at": "<string>",
        "updated_at": "<string>"
      }
    }
  ],
  "links": {
    "self": "<string>",
    "first": "<string>",
    "prev": "<string>",
    "next": "<string>",
    "last": "<string>"
  },
  "meta": {
    "current_page": 123,
    "next_page": 123,
    "prev_page": 123,
    "total_count": 123,
    "total_pages": 123,
    "next_cursor": "<string>"
  },
  "included": [
    {
      "id": "<string>",
      "type": "<string>",
      "attributes": {},
      "relationships": {}
    }
  ]
}