[CUJ] Jank CUJ: Desktop > Split Screen

Bug: 339586282
Flag: NONE jank cuj logging, not actual code change
Test: manually tests that we have newly added Cuj in perfetto trace, also check that we don't log jank if split screen transition was cancelled
Test: atest WMShellUnitTests:StageCoordinatorTests && atest WMShellUnitTests:SplitTransitionTests && atest WMShellUnitTests:SplitScreenControllerTests

Change-Id: I9b5e4ce6290aa1171c33b04934d0aae65454c90a