Gets an AgreementAccount by Id. Returns null if the AgreementAccount doesn't exist.
Success
Internal Server Error
{- "PricelistId": 0,
- "Name": "string",
- "StartDate": "2019-08-24T14:15:22Z",
- "EndDate": "2019-08-24T14:15:22Z",
- "ImageKey": "string",
- "ShowPricesIncVat": true
}