babelstone-han: change license to Arphic-1999

found at https://www.babelstone.co.uk/Fonts/Han.html#License

pkgs/data/fonts/babelstone-han/default.nix

···
     description = "Unicode CJK font with over 36000 Han characters";
     homepage = "https://www.babelstone.co.uk/Fonts/Han.html";
 
-    license = licenses.free;
+    license = licenses.arphicpl;
     platforms = platforms.all;
     maintainers = with maintainers; [ emily ];
   };