nixos/gonic: remove DynamicUser

It's not possible to let a user hand in paths that gonic should
write to if DynamicUser is used, remove it. The service should
still be sufficiently sandboxed as using chroot and only binding
paths selectively.

Signed-off-by: Paul Meyer <katexochen0@gmail.com>

nixos/modules/services/audio/gonic.nix

@@ -65,7 +65,6 @@ in
             ) cfg.settings;
           in
           "${lib.getExe cfg.package} -config-path ${settingsFormat.generate "gonic" filteredSettings}";
-        DynamicUser = true;
         StateDirectory = "gonic";
         CacheDirectory = "gonic";
         WorkingDirectory = "/var/lib/gonic";