blender: add zstandard python module

This module is needed by Flamenco addon. Without it, submitting jobs
to Flamenco manager [1] fails with:

    Error performing BAT pack: File is compressed with ZStandard,
    install the `zstandard` module to support this.

Binary Blender releases already contain this module as can be seen by
running:

    curl https://mirrors.dotsrc.org/blender/release/Blender3.6/blender-3.6.2-linux-x64.tar.xz | tar tJ | grep zstandard

[1]: https://flamenco.blender.org/

pkgs/applications/misc/blender/default.nix

@@ -79,7 +79,7 @@ stdenv.mkDerivation rec {
     ++ lib.optional cudaSupport cudaPackages.cudatoolkit
     ++ lib.optional colladaSupport opencollada
     ++ lib.optional spaceNavSupport libspnav;
-  pythonPath = with python310Packages; [ numpy requests ];
+  pythonPath = with python310Packages; [ numpy requests zstandard ];
 
   postPatch = ''
   '' +