List meters

curl --request GET \
  --url https://sandbox-api.billingrails.com/v1/meters \
  --header 'Authorization: Bearer <token>'

{
  "meters": [
    {
      "object": "meter",
      "id": "<string>",
      "created_at": "2023-11-07T05:31:56Z",
      "status": "active",
      "name": "<string>",
      "event": "<string>",
      "description": "<string>",
      "aggregation_event_property": "<string>",
      "aggregation_method": "sum",
      "account_mapping": {
        "type": "id",
        "event_property": "billingrails_account_id"
      }
    }
  ]
}