Live plot doesn't work with UDP sessions

[k1o0]

The GUI plots don't always work when using UDPs as the GUI process is completely decoupled from the main experiment process and it's the latter that gets the correct exp path from the main DAQ computer.

[bimac]

@k1o0 to find original error msg

[bimac]

This is a bit puzzling, as the online plots are called in ActiveChoiceWorldSession._run(), which should always execute after NetworkSession._init_paths() (the latter being called in BaseSession.__init__())