Motivation for this change

Update to latest version of k2pdfopt. See https://www.willus.com/k2pdfopt/k2pdfopt_version.txt for changes.

This requires the fix from #55148 in order to build, which is also included as a commit in this branch. I sent it as a separate PR in case you'd like to merge it separately.

Things done

• Tested using sandboxing (nix.useSandbox on NixOS, or option sandbox in nix.conf on non-NixOS)
• Built on platform(s)
  • NixOS
  • macOS
  • other Linux distributions
• Tested via one or more NixOS test(s) if existing and applicable for the change (look inside nixos/tests)
• Tested compilation of all pkgs that depend on this change using nix-shell -p nox --run "nox-review wip"
• Tested execution of all binary files (usually in ./result/bin/)
• Determined the impact on package closure size (by running nix path-info -S before and after)
• Assured whether relevant documentation is up to date
• Fits CONTRIBUTING.md.