Initial training time can not be changed when empty/only preset via overview

[timmwille]

This is a critical small bug, the initial training time/start can only be adjusted once there was any kind of activity in the training planner tool.

The bug even happens not just with an empty training to start with the initial time edit but also when the preselection via overview page is present but not yet any other edit in the modules or added time slot was done.

probably easy to fix but really irritating in the beginning.