Don't promote the animation on Task's parent when clearing task

We cannot promote the transition animation on Task's parent
when the task is in clearing task, in case the animation get
stuck when performing the opening task transition that behind it.

Fix: 176492094
Test: manual as issue steps in setup wizard:
1. complete initial setup without connection
2. finish the pre-deferred setup by setting up Wi-Fi connection
3. remove the Wi-Fi connection from settings page
4. launch deferred setup from notification
5. choose offline setup on Network settings page
6. complete deferred setup
7. observe the behaviour if the transition is janky when backing to home

Change-Id: I50fba3a7681c7d53e0caddf84315d6e6c76e9e92