DO NOT MERGE Do not update bar control target when application is starting

Handling the bar control target even when the application is starting
causes there to be a flicker in system bar visibility when switching
from one immersive mode app to another immersive mode app.

Bug: 149312861
Test: manual
Change-Id: If5de2ff97d4ad177e5fc58baa82b3f43ed118c2e