Move setup optimization mode to main thread

 - Due to unclear root cause of optimization mode being reset after
   reboot, update the setup logic from deferred background thread to
   main thread, to avoid any possible background task unexecuted case.

Bug: 241735485
Test: make SettingsRoboTests
Change-Id: I2de2181321712f89fadc04bf5000aea91a01485a
2 files changed