Fix wrong initial staged split position

This is caused by having set a wrong animation duration in the 3 button case. Before this change we have a fixed duration of 370ms which happens to be almost match the Overview transtion duration in gesture nav. However the transition duration in 3-button is set to 250ms. After the transition duration, any unfinished animation is cancelled including this one, resulting in the wrong staged split position. Instead this change pulls the transition duration of toState from the caller = RecentsViewStateController.

Fixes: 222210349
Test: manual
Change-Id: Ie2f3dbe38bb6df33961e2ee78b8a55d0e925501f