[AE/osxsink] - fix possible device changed loop when using passthrough

Damnit - that one slipped in when i added the registration to the default output device changed callback.

@jmarshalnz for review - Gotham material sadly.
yes ... damn :D this would change the default output device back to what it was before ... need to check again why i didn't see that issue during testing ... (it must be there imo).