[experiments] Environment "previous" relationship is not honoured by experiment configurator

The "Environment" objects have a "Previous Version" entry that point to environments they are suceeding. This information should be used by the experiment configurator to select reasonable defaults when the user forks an experiment that uses outdated environments.

My recollection is that was the case, but if I fork an experiment using "Scientific Python (0.1.0)", the default selector does not point to "Scientific Python (1.0.0)". It would be great if that was the case.

Example: https://www.beat-eu.org/platform/experiments/pkorshunov/pkorshunov/speech-pad-simple/1/speech-pad_lbp_hist_ratios_lr-pa_aligned/

Just fork it and check the default environment on the Global Parameters.