CAN FD Bitrate Switching

[Finwood]

In the PythonCANMedia class, frames are always created without the BRS flag set, even for CAN FD. This means that frames will always be sent at arbitration bitrate.

Is this intentional?

pycyphal/pycyphal/transport/can/media/pythoncan/_pythoncan.py

Lines 298 to 303 in 9514f24

	message = can.Message(
	arbitration_id=f.frame.identifier,
	is_extended_id=(f.frame.format == FrameFormat.EXTENDED),
	data=f.frame.data,
	is_fd=self._is_fd,
	)

[pavel-kirienko]

No, this is not intentional. BRS should be enabled if the FD mode is enabled. Would be nice if you added this into your #367