Fix default dict (#2025)

fix: change default to configdict

Signed-off-by: Inhyuk Andy Cho <andy.inhyuk.jo@intel.com>

Author: cih9088

otx/algorithms/common/tasks/nncf_task.py

@@ -162,7 +162,7 @@ def _prepare_optimize(self):
         # last batch size of 1 causes undefined behaviour for batch normalization
         # when initializing and training NNCF
         if self._data_cfg is not None:
-            data_loader = self._recipe_cfg.data.get("train_dataloader", {})
+            data_loader = self._recipe_cfg.data.get("train_dataloader", ConfigDict())
             samples_per_gpu = data_loader.get("samples_per_gpu", self._recipe_cfg.data.get("samples_per_gpu"))
             otx_dataset = get_configs_by_keys(self._data_cfg.data.train, "otx_dataset")
             assert len(otx_dataset) == 1