Improve logging message for prepare_transport_input script (pypsa-meets-earth#1665)

* fix: Improve logging message for file read failure in download_number_of_vehicles function

* fix: Enhance error logging for file read failure in download_number_of_vehicles function

Author: GbotemiB

scripts/prepare_transport_data_input.py

@@ -60,7 +60,9 @@ def _clean_data(df):
         )
         print("File read successfully.")
     except Exception as e:
-        logger.warning("Failed to read the file. Falling back on hard-coded data:", e)
+        logger.warning(
+            f"Failed to read the file. Falling back on hard-coded data. \nError: {e}"
+        )
         return pd.DataFrame()
 
     vehicles_gho = vehicles_gho.rename(