修复processor输出torch.tensor时被转为numpy的异常

Link: https://code.alibaba-inc.com/Ali-MaaS/MaaS-lib/codereview/10021802

    * fix to_torch_dataset

modelscope/msdatasets/ms_dataset.py

@@ -70,12 +70,12 @@ class MsIterableDataset(torch.utils.data.IterableDataset):
         for idx in range(iter_start, iter_end):
             item_dict = self.dataset[idx]
             res = {
-                k: np.array(item_dict[k])
+                k: torch.tensor(item_dict[k])
                 for k in self.columns if k in self.retained_columns
             }
             for preprocessor in self.preprocessor_list:
                 res.update({
-                    k: np.array(v)
+                    k: torch.tensor(v)
                     for k, v in preprocessor(item_dict).items()
                     if k in self.retained_columns
                 })