When a user is removed make sure we remove their persisted bubbles

- Update the NotificationLockscreenUserManager code to listen for
  account removals and notify the new listener method onUserRemoved
- Use this to trigger removals in the bubble data repository / UI

Some users may have a parent user (e.g. work profile can belong to
a parent user). We store persisted bubbles under the parent user and
have a separate field for the specific bubble user. To support this,
I pass the parent of the removed user.

Test: atest BubbleVolatileRepositoryTest BubbleDataTest
Bug: 218525763
Change-Id: Ia147cbac15ebce70bbbcc52926089f33901a99dc
Merged-In: Ia147cbac15ebce70bbbcc52926089f33901a99dc