Fix not showing divider when re-entering split with rotation

I134c8c4e keeps a split pair in the background, the split layout might
not be updated properly if the next entering split comes with rotation.
This makes sure to update the split layout to show the divider with the
correct orientation.

Fix: 280876344
Test: atest WMShellFlickerTests:DismissSplitScreenByGoHomeBenchmark
Change-Id: I47659b791cc479b92aa1d1851663d65e8a93aeab