Update messages with IPCs on a bg thread

And then once the information is retrieved,
we can update the UI back on the main thread.

Owner information + disclosure info is retrieved via an IPC,
so retrieve them both on a bg thread

Fixes: 203138561
Test: manually change owner information on the lockscreen
and check that it updates appropriately
Test: atest SystemUITests

Change-Id: I7097a0120e609c72316683f6c8438ea85cf0af8b