Support ModernBERT

[ianbulovic]

ModernBERT is currently not supported by the train system, raising a ValueError here:

cnlp_transformers/src/cnlpt/CnlpModelForClassification.py

Lines 248 to 254 in 84e784d

	raise ValueError(
	f"Encoder config does not have an attribute"
	f' "{ke.args[0]}"; this is likely because the API of'
	f" the chosen encoder differs from the BERT/RoBERTa"
	f" API and the DistilBERT API. Encoders with different"
	f" APIs are not yet supported (#35)."
	)

It looks like the ModernBERT config doesn't define hidden_dropout_prob, and instead has four different dropout config attributes: attention_dropout, embedding_dropout, mlp_dropout, and classifier_dropout. There might be other changes needed to support ModernBERT, this is just the first error that surfaces when running the train system.

[tmills]

Addressed by #228