Use queue to defer all task events

It has two layer defer currently, it should only remain queue
events method. Remove using of mDeferTaskOrgCallbacksConsumer
and extand using of queue method to onTaskAppeared,
onTaskVanished and onBackPressedOnTaskRoot.

Bug: 171749427
Test: check split screen, PiP and bubbles work normally
Change-Id: Ifb16a9fea5ef4aae0966a77d5d1674002c3cf8e3