Match setfit.Trainer Ray compatibility with Transformers

[zbloss]

Currently the setfit.Trainer class only accepts datasets.Dataset-like objects, which means I cannot pass ray.data Dataset like I would normally do when using transformers.Trainer

See ray docs for example code: https://docs.ray.io/en/latest/train/getting-started-transformers.html

Currently, passing a ray dataset fails at this line:

setfit/src/setfit/trainer.py

Line 189 in b961717

column_names = set(dataset.column_names)

Is it possible to allow SetFit to run on ray using a distributed dataset?