Start stream_audio from launch_cvd

It looks like there's an unassigned gap around port 7444, which is
easy since we have 6444 for vnc.
https://www.speedguide.net/port.php?port=7444

Enabling by default because stream_audio doesn't do any real work until
the first client connects.

Bug: 120027270
Test:  launch pie on vsoc-02, stream youtube on 7445
Change-Id: Iae815f95e0392c5eb0e8be64ffb619742d2e778a