Get all custom attributes

Example response

{
  "data": [
    {
      "attributes": {
        "case_type_id": "aeadc05e-98a8-11ec-ac2c-da7ad0900001",
        "description": "AWS Region, must be a valid region supported by AWS",
        "display_name": "AWS Region",
        "is_multi": true,
        "key": "aws_region",
        "type": "NUMBER"
      },
      "id": "aeadc05e-98a8-11ec-ac2c-da7ad0900001",
      "type": "custom_attribute"
    }
  ]
}