Get usage stats of non-prototype payment links for a gateway account

Example response

[
  {
    "payment_count": 120,
    "product": {
      "_links": [
        {
          "href": "http://products-url/v1/api/products/874h5c87834659q345698495",
          "method": "GET",
          "rel": "self"
        }
      ],
      "amount_hint": "Enter an amount in multiples of £2 for the number of permits required",
      "description": "Description of the product",
      "external_id": "874h5c87834659q345698495",
      "gateway_account_id": 1,
      "language": "en",
      "name": "A name for the product",
      "price": 1050,
      "product_name_path": "name-for-product",
      "reference_enabled": true,
      "reference_hint": "This can be found on your letter",
      "reference_label": "Amount for your licence",
      "return_url": "https://some.valid.url/",
      "service_name_path": "some-awesome-government-service",
      "status": "ACTIVE",
      "type": "DEMO"
    }
  }
]