List webhook subscriptions

{
    "status": "success",
    "data": [
        {
            "id": "b8c5b1c3-5d95-4cf0-9f2b-9f5b2b60e1a3",
            "url": "https://partner.example.com/hooks/complaints",
            "active": true,
            "created_at": "2025-10-11T15:04:05Z"
        }
    ]
}