curl --request GET \
  --url https://api.opal.dev/v1/groups/{group_id}/on-call-schedules \
  --header 'Authorization: Bearer <token>'

{
  "on_call_schedules": [
    {
      "on_call_schedule_id": "50d5e9f6-f23f-4d5a-ae91-b2640cf3975e",
      "third_party_provider": "PAGER_DUTY",
      "remote_id": "P7OWH2R",
      "name": "Customer Support On-Call"
    },
    {
      "on_call_schedule_id": "4d61592c-ed61-4b13-8f22-2fac1c49f574",
      "third_party_provider": "OPSGENIE",
      "remote_id": "72a8cb04-9e25-465d-a932-992f72077c61",
      "name": "Opal Backend On-Call"
    }
  ]
}