Sets whether SystemVoip should be suppressed so that this app's Voip can use the microphone and play incoming Voip audio. Once microphone switching functionality for the user is released, this function will no longer work. You can use
ovr_Voip_GetMicrophoneAvailability() to see if the user has allowed the app access to the microphone. This returns a
ovrSystemVoipStateHandle object which contains statuses about whether the microphone is muted or whether passthrough is enabled. ovrMessage_Voip_SetSystemVoipSuppressed will be generated in response.