correct the tests

Author: Omswastik-11

tests/test_flows/test_flow.py

@@ -314,6 +314,7 @@ def test_publish_error(self, mock_request, flow_exists_mock, get_flow_mock):
             "<oml:upload_flow>\n" "    <oml:id>1</oml:id>\n" "</oml:upload_flow>"
         ).encode()
         mock_request.return_value = response
+        flow_exists_mock.return_value = None  # Flow doesn't exist yet, so try to publish
         get_flow_mock.return_value = flow
 
         flow.publish()