Function build_amend_order_params 

pub fn build_amend_order_params(
    cmd: &ModifyOrder,
    token: String,
) -> KrakenWsAmendOrderParams

Builds WebSocket amend_order parameters from a Nautilus modify command.

Prefers venue_order_id (as order_id) over client_order_id (as cl_ord_id); cmd.client_order_id is always set so a fallback is always available.