Describe the bug
A freshly created datapack with empty NBT entries for items like Tinkers' Construct tools and Minecraft dyed leather armor overwrites the built-in rules.

Expected behavior
I'd expect empty lists in nbt_requirements, nbt_xp_values and nbt_bonuses not to overwrite the built-in files. Maybe have them only do so when "override": true?

To Reproduce
Steps to reproduce the behavior:

1. Fresh game with PMMO
2. Make dyed leather chestplate
3. Create empty datapack
4. Do /reload
5. No more xp_bonuses.

Versions:
All current PMMO versions.

Additional context
This emotive cat:

Another option could be to just make users block the specific files if they want to override the built-in ones, though that doesn't help 1.18 users.

🤔 I've always held the perspective that NBT config entries consist of a comprehensive idea of configurations. However, if datapacks that weren't overriding were simply added to the end of the logic sequence, then we could have them combine. It would just have to be a consideration of the implementation, which is perfectly fine.