[Incompatibility] Data Attributes/PlayerEx crashes on world join (due to Registry Mixin?)

[muon-rw]

Mod Name

Data Attributes

Mod Homepage

https://github.com/PlayerEXDirectorsCut/data-attributes

Minecraft version

1.20.1

Describe the bug

Crash on world creation

Steps to reproduce

1. Install Data Attributes and PlayerEx (the forks for 1.20.1 linked)
2. Create or Join a world

Logs

https://mclo.gs/0ilMlU8

Additional context

Data Attributes uses a mixin to be able to modify the attribute registry dynamically, allowing entity attributes to be modified and created with datapacks on world join/reload.

This mod is a dependency for PlayerEx, one of the most popular skills mods.

### How to fix
- [ ] Redirect uses of MappedRegistry fields inside mixins to the method equivalents (Forge ignores fields such as `byKey`)
- [ ] Alternatively, modify NamedspacedWrapper to care about the vanilla fields