Update flicker tests for new shell transition

The shell transition is now consistent with the legacy one. So we
don't need to take the divider bar as a reference. Update it to match
the new transition.


Bug: 258241450
Test: atest WMShellFlickerTests:DismissSplitScreenByDivider
Change-Id: Ib5dbfe6d90e03efd6b3c0951fb87226272146496
1 file changed