Support getting `paymentMethodShortName` from `getPaymentMethods()` API call
This issue requests getting `paymentMethodShortName` from `getPaymentMethods()` API call.

It's currently returned as part of `trade.offer.paymentMethodShortName`.

The solution should be tested in the [haveno-ts](https://github.com/haveno-dex/haveno-ts) project.