fix useless error msg in nnunetv2runner (Project-MONAI#7217)

Fixes # fix useless error msg in nnunetv2runner

### Description

### Types of changes
- [x] Non-breaking change (fix or new feature that would not break
existing functionality).

Signed-off-by: elitap <elias.tappeiner@gmx.at>
Signed-off-by: Juan Pablo de la Cruz Gutiérrez <juampatronics@gmail.com>

monai/apps/nnunet/nnunetv2_runner.py

@@ -275,8 +275,8 @@ def convert_dataset(self):
                 num_input_channels=num_input_channels,
                 output_datafolder=raw_data_foldername,
             )
-        except BaseException:
-            logger.warning("Input config may be incorrect. Detail info: error/exception message is:\n {err}")
+        except BaseException as err:
+            logger.warning(f"Input config may be incorrect. Detail info: error/exception message is:\n {err}")
             return
 
     def convert_msd_dataset(self, data_dir: str, overwrite_id: str | None = None, n_proc: int = -1) -> None: