For #36143: Explicitly closing download_attachment file handler (#114)

We want to ensure that we're explicitly closing our file handler in download_attachment, so that we don't throw an error in cases where Python's garbage collector doesn't close the file.

Author: victoriagrey

shotgun_api3/shotgun.py

@@ -1612,6 +1612,8 @@ def download_attachment(self, attachment=False, file_path=None,
             raise ShotgunFileDownloadError(err)
         else:
             if file_path:
+                if not fp.closed:
+                    fp.close()
                 return file_path
             else:
                 return attachment