add load_datasete data_dir parameter (#5747)

examples/text_to_image/train_text_to_image_flax.py

@@ -275,6 +275,7 @@ def main():
             args.dataset_name,
             args.dataset_config_name,
             cache_dir=args.cache_dir,
+            data_dir=args.train_data_dir
         )
     else:
         data_files = {}

examples/text_to_image/train_text_to_image_lora_sdxl.py

@@ -768,6 +768,7 @@ def main(args):
             args.dataset_name,
             args.dataset_config_name,
             cache_dir=args.cache_dir,
+            data_dir=args.train_data_dir
         )
     else:
         data_files = {}