Add 'Only White Unmuted' as an In-Game Overlay Display Option

Currently the only option for displaying users on the in-game overlay beyond 'always' and 'never' is 'only while speaking', which is useful for when there are too many people in a voice channel for the 'always' option to be sensible, but does mean that when several people talk their names move up and down a lot which makes the overlay less useful. Therefore it would be useful to have an 'only while unmuted' option in addition to the others, so that users who aren't talking at all don't take up space, while those that are participating can remain displayed in the moments when they aren't speaking.