Bump tough-cookie and npm-check-updates in /doc-sites

Removes [tough-cookie](https://github.com/salesforce/tough-cookie). It's no longer used after updating ancestor dependency [npm-check-updates](https://github.com/raineorshine/npm-check-updates). These dependencies need to be updated together.


Removes `tough-cookie`

Updates `npm-check-updates` from 7.0.2 to 16.10.15
- [Release notes](https://github.com/raineorshine/npm-check-updates/releases)
- [Changelog](https://github.com/raineorshine/npm-check-updates/blob/main/CHANGELOG.md)
- [Commits](https://github.com/raineorshine/npm-check-updates/compare/v7.0.2...v16.10.15)

---
updated-dependencies:
- dependency-name: tough-cookie
  dependency-type: indirect
- dependency-name: npm-check-updates
  dependency-type: direct:development
...

Signed-off-by: dependabot[bot] <support@github.com>
2 files changed