Fix divider display issue

onDisplayAreaInfoChanged might callback many times in one action
such like fold to unfold, it might cause some issues because we
don't use lastet config resources to set SplitLayout.

Another bug is we cannot get divider leash immediately after we
init it because leash is built after attachToParentSurface.

Fix both bug by always do whole SplitLayout setting if any cared
configs changed. And add a callback after divider leash build,
show the leash on this callback to ensure we got null leash.

Fix: 198581512
Fix: 197296095
Test: manual
Test: pass existing tests
Change-Id: I06a4093927d6469a85b2104b36c16d6e16519a51