String gets cast to int despite correct OpenAPI spec

[valentin-pauline]

> restish staging create-portfolio-withdrawal

restish create-portfolio-withdrawal amount: string

> restish staging create-portfolio-withdrawal amount: "100000000000" -vv

POST /platform/v0/portfolios/019d2b1f-5ea5-7791-affa-c43a17c5edf4/withdrawals HTTP/1.1
..headers omitted..

{"amount":100000000000}

The amount field gets cast to an int in json by restish, even though the OpenAPI spec says it should be a string