weechatScripts.weechat-xmpp: remove

This plugin is fairly outdated and depends on python2 libraries that
don't receive any updates either (xmpppy for instance[1]).

[1] https://pypi.org/project/xmpppy/

pkgs/applications/networking/irc/weechat/scripts/default.nix

@@ -1,10 +1,6 @@
 { callPackage, luaPackages }:
 
 {
-  weechat-xmpp = callPackage ./weechat-xmpp {
-    inherit (pythonPackages) pydns;
-  };
-
   weechat-matrix-bridge = callPackage ./weechat-matrix-bridge {
     inherit (luaPackages) cjson luaffi;
   };