Unlock user 0 before unlocking other user

- For normal flow, starts/unlocks user0 in main boot up thread.
  Seding it to background thread brought lots of lock contention due
  to locks in AMS / PMS. Improving locks there may allow running in background
  in future.
- For foreground user, only start it and postpone unlock until boot complete.
  TODO: Unlock foreground user as well before boot complete.
- The issue of unlocking twice should be fixed separately.

Bug: 124797617, 124460424
Test: Boot the system and check if all users are unlocked.

Change-Id: I83b94bd3ffcb928462d607563f7b5f09d8bfe378