build(deps): bump nanoid and mocha in /testing

Removes [nanoid](/~https://github.com/ai/nanoid). It's no longer used after updating ancestor dependency [mocha](/~https://github.com/mochajs/mocha). These dependencies need to be updated together.


Removes `nanoid`

Updates `mocha` from 10.2.0 to 10.8.2
- [Release notes](/~https://github.com/mochajs/mocha/releases)
- [Changelog](/~https://github.com/mochajs/mocha/blob/main/CHANGELOG.md)
- [Commits](mochajs/mocha@v10.2.0...v10.8.2)

---
updated-dependencies:
- dependency-name: nanoid
  dependency-type: indirect
- dependency-name: mocha
  dependency-type: indirect
...

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