Rebind bundle header to newly activated view-model

Flag: com.android.systemui.notification_bundle_ui
Fixes: 421770153
Test: manual
  1. receive some bundled notifications
  2. without expanding bundle, swipe bundle away
  3. receive new notification in same bundle
  Observe: icons are not stale
Change-Id: I85664ca1a0eaf674f88c747154f6d1756273fded