Improve SetClientMuteType Functions to allow Session Mutes/Gags

[DJPlaya]

Hi, I am currently implementing Material Admin in my Plugins which do handle Cheats and Exploits. For an Voice Loopback Blocker, it would be really useful to perform an Session mute, so that the Client is unmuted/ungagged once he fully reconnects. If you need Assistance, take a look at SourceComms, the Native SourceComms_SetClientMute can be provided with -1 for the muteLenght to for an Session Mute.