Improved mixin target for `WorldSettingsImport`

[alcatrazEscapee]

The issue: In the case of, for example, an erroring configured feature, a blame report was getting printed for every subsequent resource as well. This had several issues:

• It obscures the actual helpful error
• It falsely informs the user that there are errors with files that don't have any error at all.

I've moved the mixin to, what I believe, is a better location - catching the data result for the element before it's flat-mapped into the "result" DataResult, and adjusted the surrounding infrastructure to handle this new injection point. Notably, this location can be invoked for the same file (for instance, every time a configured feature is referenced by a biome), and so a "seen already" mechanism was added to avoid duplicating similar error messages.

@TelepathicGrunt I don't know what kind of code style or contribution mumbo jumbo you want here, so I tried to be as consistent with existing code - where there was consistency - as possible

[TelepathicGrunt]

Awesome thank you! I'm more laid back with code styles (and you can see how my code style slowly changes over time by looking at my older code lol). As long as the PRs works and it is easy to read and understand the code, it's good to me! I'll merge this in ASAP.

Would you like credit in the changelog and/or also added as a contributor on the curseforge page?

[alcatrazEscapee]

Nah, don't worry about it.