Use alternative way to fix split select page snapping issue

- Reverted to before ag/16095449 where reset() is called after state transition completed
- Call pageBeginTransition in dismiss animation to make sure onPageEndTransition is triggered to clear mCurrentPageScrollDiff properly
- Fixed a condition in resetFromSplitSelectionState ot use DeviceProfile.overviewShowAsGrid, as when state is in transition, showAsGrid() would be false

Fix: 207744890
Test: manual
Change-Id: I5a812a7ee26df2f953f7fed0155880620d2c4e66