Get the custom hostnames for this environemnt

curl --request GET \
  --url https://app.dynamicauth.com/api/v0/environments/{environmentId}/custom/hostnames

{
  "customHostnames": [
    {
      "id": "95b11417-f18f-457f-8804-68e361f9164f",
      "hostname": "auth.dynamic.xyz",
      "status": "active",
      "verificationRecords": [
        {
          "dnsRecordType": "TXT",
          "verificationType": "certificate",
          "name": "<string>",
          "value": "<string>"
        }
      ],
      "errors": "<string>"
    }
  ]
}