[BUG]: Midi1 port numbers are off by one in in-box SDK dev preview 1

[Psychlist1972]

Need to subtract 1 as was done in the previous SDK, Right now, they are not correct.

// for MIDI Input (Source) ports, we have to subtract 1 because we number in the service starting at 1
// For midi Output (Destination) ports, we leave the number as-is, because the GS synth occupies number 0

SDK test on left, midi1enum output on right