chore(deps-dev): bump @ember/test-helpers from 3.3.1 to 4.0.4

Bumps [@ember/test-helpers](https://github.com/emberjs/ember-test-helpers) from 3.3.1 to 4.0.4.
- [Release notes](https://github.com/emberjs/ember-test-helpers/releases)
- [Changelog](https://github.com/emberjs/ember-test-helpers/blob/master/CHANGELOG.md)
- [Commits](https://github.com/emberjs/ember-test-helpers/commits)

---
updated-dependencies:
- dependency-name: "@ember/test-helpers"
  dependency-type: direct:development
  update-type: version-update:semver-major
...

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