kitty: remove unused nativeBuildInputs on macOS

These two dependencies were used to generate the PNG icons that would later be converted to the icon for the macOS app. The PNGs are now stored in git and are not generated during the build anymore.

pkgs/applications/misc/kitty/default.nix

@@ -12,8 +12,6 @@
   libcanberra,
   libicns,
   libpng,
-  librsvg,
-  optipng,
   python3,
   zlib,
 }:
@@ -55,8 +53,6 @@ buildPythonApplication rec {
   ] ++ stdenv.lib.optionals stdenv.isDarwin [
     imagemagick
     libicns  # For the png2icns tool.
-    librsvg
-    optipng
   ];
 
   propagatedBuildInputs = stdenv.lib.optional stdenv.isLinux libGL;