Bump js-yaml and mocha in /ember-electron/backend

Bumps [js-yaml](https://github.com/nodeca/js-yaml) to 4.2.0 and updates ancestor dependency [mocha](https://github.com/mochajs/mocha). These dependencies need to be updated together.


Updates `js-yaml` from 3.13.1 to 4.2.0
- [Changelog](https://github.com/nodeca/js-yaml/blob/master/CHANGELOG.md)
- [Commits](nodeca/js-yaml@3.13.1...4.2.0)

Updates `mocha` from 6.1.4 to 11.7.6
- [Release notes](https://github.com/mochajs/mocha/releases)
- [Changelog](https://github.com/mochajs/mocha/blob/v11.7.6/CHANGELOG.md)
- [Commits](mochajs/mocha@v6.1.4...v11.7.6)

---
updated-dependencies:
- dependency-name: js-yaml
  dependency-version: 4.2.0
  dependency-type: indirect
- dependency-name: mocha
  dependency-version: 11.7.6
  dependency-type: direct:development
...

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

Author: dependabot[bot]