tauon: turn discord rpc on by default

upstream includes this on by default, and it's more convenient for users
if they don't have to turn this on both in application settings, and
in the derivation arguments.

discord rpc doesn't take up a lot of space or time to build either,
as it's just an additional pythong module.

Author: huantianad

pkgs/applications/audio/tauon/default.nix

@@ -23,7 +23,7 @@
   wavpack,
   ffmpeg,
   pulseaudio,
-  withDiscordRPC ? false,
+  withDiscordRPC ? true,
 }:
 
 stdenv.mkDerivation (finalAttrs: {