Can you try to print connection_handle? It should return -> <dataikuapi.dss.admin.DSSConnection object at 0x7f6326340040>
You seem to be using a cursor attribute later, which does not exist for this object.
In this instance, you would need to retrieve the params you need dssclient.get_connection().get_info() check the connection attributes and pass these individually to your sqlite. Given the user has sufficient permission to read the connection information.
However, DSS provides SQLExecutor2 which should work in this case where you can just pass the connection name.