BHV-15606: VideoPlayer slider not updating on switch from full to inline when paused

### Issue:
we changed videoplayer to not update inline controls when full-screen, and vice-versa. This resulted in the slider not updating, when paused.
### Fix:
call updatePosition() on fullscreenChanged()

Enyo-DCO-1.1-Signed-off-by: Krishna Rangarajan <krishna.rangarajan@lge.com>