[client] audio: change the audio latency graph sample point

This removes the need for locking while also giving a better result in
the graph output. Also when the graph is disabled via the overlay
options it will no longer cause redraws.

client/src/main.c

@@ -155,8 +155,6 @@ static bool tickTimerFn(void * unused)
   if (needsRender)
     app_invalidateWindow(false);
 
-  audio_tick(tickCount);
-
   ++tickCount;
   return true;
 }