Only clear launch bounds if split is launching with active bubbles

Bubbled tasks have bounds set. Tasks launched in split should not have
specific bounds set as they need to inherint them from parent.

When launching split screen via an intent, we don't know if an existing
bubble will be reused or not. Previously we were always clearing the
launch bounds when a task moved to split. But this caused performance
regressions with launching split screen.
Limit clearing of the launch bounds to only scenario when there are
active bubbles. We still do not know if the existing bubble will be used
for the split screen, but if there are bubbles present, it might.
And if there are no bubbles, we can know for certain that an existing
bubbled task is not used. And we do not need to clear bounds.

Bug: 422665646
Test: atest WMShellUnitTests:StageCoordinatorTests
Test: manual, have Calculator in a bubble, start split screen using
  Clock from home screen, select Calculator as the second split app,
  observe that Clock and Calculator and Clock start in split screen with
  correct bounds
Flag: com.android.wm.shell.enable_enter_split_remove_bubble
Change-Id: I655ff78adffca0322f8fc271a56f0425696eb281