Use obtainMessageO for sendTimeShiftMode

It seems the obtainMessageI doesn't work for single argument results for some reason. Using obtainMessageO is more consistent with the rest of the implementations anyway. This fixes a crash when trying to access the args, which are null.

Bug: 269185572
Test: atest TvInteractiveAppServiceTest
Change-Id: I94fd4b87dbe09b282541785718996263170c85da