libobs: Fix for monitoring deduplication edge case
When an 'Audio Capture Source' device is also used for monitoring, the
deduplication logic is applied: all monitored sources are silenced.
But this should not silence the 'Audio Capture Source' if for some
reason, it is being monitored (the user will get echoes, but hey, it's
their choice). So we exclude the 'Audio Capture Source' from the
silenced sources.
Signed-off-by: pkv <[email protected]>