Prevent a few crashes that occur when advancing the SB CD flag to staging

1. An IllegalStateException that occurs when reloading the fragments
   in FragmentHostManager
2. A ConcurrentModificationException in StatusBarContentInsetsProvider
   when notifying listeners.
3. A NPE in SystemEventChipAnimationControllerImpl when an animation
   finishes.

Test: advance the flag to staging
Bug: 362720336
Flag: EXEMPT trivial
Change-Id: I3a2479e29ef3260c3eb218f4786e962cf122772c