Check jsonl ext in quantize.py so local datasets can also be used

Signed-off-by: Asha Anoosheh <aanoosheh@nvidia.com>

Author: AAnoosheh

examples/post_training/modelopt/quantize.py

@@ -236,7 +236,7 @@ def get_calib_dataloader(
 
     Supports either a local path (.jsonl) or a HuggingFace dataset name.
     """
-    if os.path.isfile(dataset_path_or_name):
+    if os.path.isfile(dataset_path_or_name) and dataset_path_or_name.endswith(".jsonl"):
         # Local file
         print_rank_0(f"Loading calibration dataset from local file: {dataset_path_or_name}")
         all_texts = []