move configure_packing to llamafactory.model.patcher and fix constants

src/llamafactory/hparams/data_args.py

@@ -86,7 +86,9 @@ class DataArguments:
     )
     efficient_packing: Optional[bool] = field(
         default=None,
-        metadata={"help": "Whether or not to pack the sequences without cross-contamination attention for efficient training."},
+        metadata={
+            "help": "Whether or not to pack the sequences without cross-contamination attention for efficient training."
+        },
     )
     tokenized_path: Optional[str] = field(
         default=None,