**What happened**:

With the new Backport providers, when calling `DataflowCreatePythonJobOperator` with an empty `py_rerquirments` Dataflow commands always launch inside a virtualenv.

**What you expected to happen**:

The Dataflow command should run locally.


tests/providers/google/cloud/hooks/test_dataflow.py
self, mock_conn, mock_dataflow, mock_dataflowjob, mock_uuid
    ):
        mock_uuid.return_value = MOCK_UUID
        mock_conn.return_value = None