This fixes the issue where the labels wouldn't have enough space for
localization text in certain circumstances, and also fixes some issues
with alignment
Implement the signals for the mixer checkboxes in the advanced audio
control so that it properly relays the values to/from the source when
the mixers are changed in obs or when the mixers are changed by the
user.
In the advanced audio properties, the last set of controls designate
what tracks the audio of a specific source is applied to, but for some
reason I named it 'Media Channels'. It feels a bit confusing of a name.
I feel like it should really just be called 'Tracks' here for lack of a
better term.
This dialog gives options such as increasing audio past 100%, forcing
the audio of a source to mono, and setting the audio sync offset of a
source (which was an oft-requested feature)
