[Audiences] Get Existing Audiences

curl --request GET \
  --url 'https://api.criteo.com/legacy/marketing/v1/audiences?advertiserId=1234' \
  --header 'Accept: application/json'

{
  "audiences": [
    {
      "id": 9999,
      "advertiserId": 1234,
      "name": "Custom Audience",
      "description": "Custom Audience for Retargeting Campaign",
      "created": 1559902356,
      "updated": 1584504000,
      "nbLines": 392403,
      "nbLinesEmail": 392403,
      "nbMatchesEmail": 276000
    },
    {
      "id": 7777,
      "advertiserId": 1234,
      "name": "Lapsed Users Audience",
      "description": "Lapsed Users Audience for Prospecting Campaign",
      "created": 1559914086,
      "updated": 1584504000,
      "nbLines": 2914455,
      "nbLinesEmail": 2914455,
      "nbMatchesEmail": 1890392
    }
  ]
}