Merge changes Id9f81fdf,I3428e8b3,Ifa895f71,I61cd4751,I47a25e9f into main

* changes:
  Add tests for always on lockdown VPN on system user.
  Remove MockVpn.setAlwaysOnPackage() non-lockdown.
  Mock onUserAdded() and onUserRemoved()
  Refactor helper method to return integer ranges.
  Add tests for onUserAdded and onUserRemoved