remove un-necessary check

Signed-off-by: varun-edachali-dbx <varun.edachali@databricks.com>

Author: varun-edachali-dbx

src/databricks/sql/backend/thrift_backend.py

@@ -583,8 +583,6 @@ def open_session(self, session_configuration, catalog, schema) -> SessionId:
             response = self.make_request(self._client.OpenSession, open_session_req)
             self._check_initial_namespace(catalog, schema, response)
             self._check_protocol_version(response)
-            if response.sessionHandle is None:
-                raise DatabaseError("Server returned null session handle")
             info = (
                 {"serverProtocolVersion": response.serverProtocolVersion}
                 if response.serverProtocolVersion