Fix crash when SelectInterp is empty.

The lidarStream seems to be started two times. The first time when we set the lidar source (the toggle button is checked, which emit a toggle signal then start the stream in onToggle slot), the second time when the openSensorReaction is triggered.

So we are in a race condition case after the second stream starts. Because of that, in some time SelectInterp appear to be null in PacketConsumer::HandleSensorData and an assert is thrown from a MetaPacketInterpreter macro.

@nick.laurenson, @melanie.carriere PTAL