Update grobid_client/grobid_client.py

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

Author: lfoppiano

grobid_client/grobid_client.py

@@ -584,8 +584,8 @@ def process_pdf(
             return self._handle_request_error(pdf_file, e)
         except Exception as e:
             return self._handle_unexpected_error(pdf_file, e)
-        finally:
-            pdf_handle.close()
+            if pdf_handle is not None:
+                pdf_handle.close()
 
     def get_server_url(self, service):
         return self.config['grobid_server'] + "/api/" + service