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

quickstep/src/com/android/quickstep/views/RecentsView.java

@@ -3185,6 +3185,7 @@ public abstract class RecentsView<ACTIVITY_TYPE extends StatefulActivity<STATE_T
                                 }
                             }
                         }
+                        pageBeginTransition();
                         setCurrentPage(pageToSnapTo);
                         // Update various scroll-dependent UI.
                         dispatchScrollChanged();
@@ -4024,7 +4025,7 @@ public abstract class RecentsView<ACTIVITY_TYPE extends StatefulActivity<STATE_T
 
     /** TODO(b/181707736) More gracefully handle exiting split selection state */
     private void resetFromSplitSelectionState() {
-        if (!showAsGrid()) {
+        if (!mActivity.getDeviceProfile().overviewShowAsGrid) {
             int pageToSnapTo = mCurrentPage;
             if (mSplitHiddenTaskViewIndex <= pageToSnapTo) {
                 pageToSnapTo += 1;