Revert "Relax permission checks in sound trigger middleware"

This is a rollback of ag/10525952, since the underlying issue
is was working around has been addressed.

Bug: 151281856
Test: Some people have reported this to work. I'm still seeing issues
      on Sargo, and want more rigorous testing done by QA, owners of
      Now Playing, and owners of the permission subsystem.
Change-Id: I711470fa4f8478bce74d94ca403b029dd9a1bbd7