Get subscription details

curl --request GET \
  --url https://api.suby.fi/api/subscription/{subscriptionId} \
  --header 'X-Suby-Api-Key: <api-key>'

{
  "success": true,
  "data": {
    "id": "sub_abc123",
    "productId": "<string>",
    "productName": "<string>",
    "status": "ACTIVE",
    "customerEmail": "jsmith@example.com",
    "createdAt": "2023-11-07T05:31:56Z",
    "expiresAt": "2023-11-07T05:31:56Z"
  }
}