Describe the bug
When the player joins a world a PlayerData instance will be assigned to the PREVIEW_DATA field. This field will never be updated and thus the first player entity instance and its world will stay in memory for ever.

To Reproduce
Steps to reproduce the behavior:

1. Join world
2. Leave world
3. See WorldClient instance not being garbage collected

Context (please complete the following information):

• Minecraft version: 1.12.2
• Forge version: 14.23.5.2855
• Mo' Bends version: 1.1.0

Fixed in my fork