Move bubble setting to secure table & support multiuser

* Move bubbles setting from the global table to the secure
  table, this should be a per-user setting
* Update step in SettingsProvider that adds the secure
  setting based on the value of the previous global, or if
  the user is managed, it checks if the owner of the managed
  user has a secure setting & uses the value from that to
  insert the new setting.
* Adds the secure setting to the "cloned to profile"
  group since it should follow the setting of the profile
  owner.
* PreferencesHelper tracks this value per-user.

Bug: 173408780
Test: atest PreferencesHelperTest NotificationManagerServiceTest BubbleExtractorTest
Change-Id: I261364890fcc54fb2791e628b41c07aeddde3974