Fix seeking (go to time) from data input and behavior API

There is something odd when trying to jump to a given time via QSlidePlayer::seek(). It seems that it can only seek once during one run of the animation. (e.g. try jumping to 5000 ms in a default 10 sec timeline multiple times - the first attempt will succeed, the others will get ignored until the animation (if looping) restarts)

Can be tested with tests/scenes/behaviors/actionevent.uip for example. (just hit the Jump cone a couple of times)