Poll Document Collection submissions received since a point in time

curl 'https://api.expiryedge.com/v1/listCollectionSubmissions?since=2026-09-01T00%3A00%3A00Z&limit=50' \
  -H "Authorization: Bearer $EXPIRYEDGE_API_KEY"

{
  "data": [
    {
      "id": "sub_Qm3r",
      "request_id": "req_9WkT",
      "template_id": "tpl_W9onboard",
      "submitted_at": "2026-09-26T16:42:10.000Z",
      "review_status": "pending",
      "revision": 1,
      "responses": {
        "fld_company_name": "Northwind Dental LLC"
      },
      "files": [
        {
          "field_id": "fld_insurance",
          "name": "liability-certificate-2026.pdf",
          "content_type": "application/pdf",
          "size": 482113
        }
      ]
    }
  ],
  "next_cursor": "WyIyMDI2LTA5LTI2VDE2OjQyOjEwLjAwMFoiLCJzdWJfUW0zciJd",
  "has_more": false
}