feat: add batch size of map function in the preprocessed dataset

Former-commit-id: 94b6cf06c2f84d0619b1a2dccaf8abb51de9951c

src/llamafactory/hparams/data_args.py

@@ -109,6 +109,10 @@ class DataArguments:
         default=None,
         metadata={"help": "Path to save or load the tokenized datasets."},
     )
+    dataset_map_batch_size: Optional[int] = field(
+        default=None,
+        metadata={"help": "Batch size for dataset mapping."},
+    )
 
     def __post_init__(self):
         def split_arg(arg):