SIENTIAPDE-1193

Update Gates activity and format_and_export_prediction workflow to use DATETIME_FORMAT_WITH_TZ for consistent timestamp handling

- Modified Gates activity to correctly handle the maximum timestamp without formatting it prematurely.
- Updated format_and_export_prediction workflow to utilize DATETIME_FORMAT_WITH_TZ for timestamp conversion.
- Enhanced tests to ensure timestamp conversion is applied consistently across workflows.

laborious/activities/gates.py

@@ -322,7 +322,7 @@ class Gates(BaseActivity):
             return now().strftime(DATETIME_FORMAT_WITH_TZ)
 
         max_timestamp = max(
-            data['timestamp'].values.tolist()).strftime(DATETIME_FORMAT_WITH_TZ)
+            data['timestamp'].values.tolist())
 
         self.info(
             f"Last timestamp: {max_timestamp}", metadata)