fix possible crash when trading and using containers
fix possible crash when trading and using containers

gpedro/otclient,dreamsxin/otclient,Radseq/otclient,dreamsxin/otclient,Cavitt/otclient_mapgen,EvilHero90/otclient,kwketh/otclient,kwketh/otclient,Radseq/otclient,gpedro/otclient,gpedro/otclient,EvilHero90/otclient,dreamsxin/otclient,Cavitt/otclient_mapgen