Update AAudioStreamBuilder_setPackageName notes

We discovered that requestStart sometimes returns -896,
an internal error. This error comes from mic permissions
not being correct on input streams when an invalid package
name is used. This fix is to update documentation.

Bug: 193684488
Test: Tested with OboeTester and ran Oboe tests
Change-Id: I76c0ff59a3a0c51f01471ad8d06fbff25b629436