Update an existing dynamic ad

{
  "measurementDynamicAd": {
    "name": "The Pod Show - Mid-Roll",
    "uid": "ad-123-456",
    "cohortsAttributes": [
      {
        "cohortName": "Creative",
        "subCohortName": "Holiday 30s"
      }
    ]
  }
}

{
  "measurementDynamicAd": {
    "id": "0123456789abcdef",
    "name": "The Pod Show - Mid-Roll",
    "uid": "ad-123-456",
    "cohorts": [
      {
        "cohortName": "Creative",
        "subCohortName": "Holiday 30s"
      }
    ],
    "campaign": {
      "id": "0123456789abcdef",
      "name": "Brand Campaign Q2",
      "startDate": "2024-03-01",
      "endDate": "2024-03-01",
      "customEvents": [
        {
          "id": 1,
          "label": "Signup",
          "pattern": "example.com/sign_up"
        }
      ],
      "pixel": {
        "id": "0123456789abcdef",
        "name": "Attribution Pixel",
        "brand": {
          "crmBrandId": "brand_0123456789abcdef",
          "name": "ACME Corp., Inc.",
          "domain": "acme.com"
        }
      }
    },
    "flights": [
      {
        "startDate": "2024-03-01",
        "endDate": "2024-03-31"
      }
    ]
  }
}