Altering player file in resource pack breaks custom skins and capes

When attempting to add anything to the player file in the resource pack, custom skins created in the dressing room and capes will not be available.

Steps To Reproduce:

1. Copy the player resource file to a resource pack
2. Add something new to the file; a variable, animation, geometry, texture, etc.
3. Apply the pack and load a world
4. Capes and Dressing Room skins will not show in game

Expected Behavior:

• Altering the player resource file doesn't break dressing room skins or capes

Actual Behavior:

• Dressing Room skins and capes aren't shown in game