Change the content type of generated XMLs in storage metadata (#728)

* Change the content type of generated XMLs in storage metadata

* Add content disposition header to generated XMLs

* Update dependencies

Author: danniel

backend/donations/views/download_donations/byof.py

@@ -98,6 +98,9 @@ def handle_external_data_processing(own_upload_id: int) -> dict | None:
 
     # Save to FileField
     own_upload.result_data.save("data.xml", xml_file, save=False)
+    own_upload.result_data.storage.object_parameters.update(
+        {"ContentType": "application/octet-stream", "ContentDisposition": "attachment"}
+    )
     own_upload.status = OwnFormsStatusChoices.SUCCESS
     own_upload.save()