Bug Duplication

[AkuGatau19]

Issue description

/ah When we want to buy an item, we can dupe it by pressing the item we want to buy, then pointing to the emerald block

Video : https://drive.google.com/file/d/1iCBUUhuTYVQbkge3Ml9Be9TI6l6ZlbzG/view?usp=drivesdk

Steps to reproduce the issue

OS and versions

• PocketMine-MP: 4.9.0
• Plugin version: 2.0.1
• Server OS: 8.0.22

Error/Crash log (If available)