libndp: 1.6 -> 1.7 (#42003)

Semi-automatic update generated by https://github.com/ryantm/nixpkgs-update tools.

This update was made based on information from https://repology.org/metapackage/libndp/versions.

These checks were done:

- built on NixOS
- /nix/store/772l53fskv0f58v9bqlszf6ggymdzczf-libndp-1.7/bin/ndptool passed the binary check.
- 1 of 1 passed binary check by having a zero exit code.
- 0 of 1 passed binary check by having the new version present in output.
- found 1.7 with grep in /nix/store/772l53fskv0f58v9bqlszf6ggymdzczf-libndp-1.7
- directory tree listing: https://gist.github.com/7b9d9ce7d36f0cafaa401244d6a6230f
- du listing: https://gist.github.com/b53fc0582f55a83e692df8f85c980447