Allow a specific microphone to be used by the ffmpeg audio pipeline utility functions. Default to using the currently active microphone on Mac (#31846)
* use currently active microphone on mac for ffmpeg_microphone
* Allow ffmpeg_microphone device to be specified
Co-authored-by: amyeroberts <22614925+amyeroberts@users.noreply.github.com>
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Co-authored-by: amyeroberts <22614925+amyeroberts@users.noreply.github.com>