qa/tasks/vstart_runner: add optional "sudo" param to _run_python()
to silence mypy warnings like:
tasks/vstart_runner.py:691: error: Definition of "_run_python" in base class "LocalCephFSMount" is incompatible with definition in base class "CephFSMount"
tasks/vstart_runner.py:705: error: Definition of "_run_python" in base class "LocalCephFSMount" is incompatible with definition in base class "CephFSMount"