Get a subscription item applied discount.

curl -X GET \
 /subscription-item-applied-discounts/{id} \
 --header "Authorization: Bearer <token>"

{
  "id": "<string>",
  "subscriptionItem": "https://example.com/",
  "coupon": "https://example.com/",
  "status": "<any>",
  "discount": {
    "name": "10% off",
    "type": "<any>",
    "percentage": 10,
    "fixedAmount": {},
    "frequency": "<any>",
    "frequencyInterval": 3
  },
  "appliedIntervals": 1,
  "createdAt": "2023-11-07T05:31:56Z",
  "updatedAt": "2023-11-07T05:31:56Z",
  "removed": true,
  "completed": true,
  "active": true,
  "tenantId": "<string>"
}