CDB3-323 basicSell-dutch check swagger client crash on itemProps field

Summary: check swagger client correctly rendering schema

STR:

1. Go to https://procedure-dev.prozori.in.ua/api/doc#/ - Procedure - basicSell-dutch.BasicSellDutchProcedure - items - 'itemProps' field
2. Check screenshot

Actual result: https://prnt.sc/ywf871

Expected result: https://prnt.sc/ywfa3c fix render to be like in BSE