PackageManager: Fix logic around upgrading text display

* This code has all threads writing into the integer keeping track of
  the number of packages at once.
* Make this integer an atomic one, preventing all threads from racing
  when updating it.

Change-Id: I727306f8ab20edb7ec2a955ca20e6de0146c7737
SystemUI: Expose heads up.

Signed-off-by: Roman Birg <roman@cyngn.com>
Signed-off-by: Adnan Begovic <adnan@cyngn.com>
Change-Id: I276cb1c80d392b7dbac28e5f553207415b558481