Bump @ember/test-helpers from 2.4.2 to 2.6.0 (#991)

Bumps [@ember/test-helpers](https://github.com/emberjs/ember-test-helpers) from 2.4.2 to 2.6.0.
- [Release notes](https://github.com/emberjs/ember-test-helpers/releases)
- [Changelog](https://github.com/emberjs/ember-test-helpers/blob/master/CHANGELOG.md)
- [Commits](emberjs/ember-test-helpers@v2.4.2...v2.6.0)

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

Signed-off-by: dependabot[bot] <[email protected]>

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

yarn.lock

@@ -1182,9 +1182,9 @@
     ember-cli-babel "^7.26.6"
 
 "@ember/test-helpers@^2.4.2":
-  version "2.4.2"
-  resolved "https://registry.yarnpkg.com/@ember/test-helpers/-/test-helpers-2.4.2.tgz#e5be97e316dc502d7da933461135fbcb9254726e"
-  integrity sha512-++k/dXZ0IeOQLSm0Yu5QuCRe9UoptuckMhaXHY37VLb1varLHRuP8908kigVNt9c5waiocaK4jPjDBkKYRLlfA==
+  version "2.6.0"
+  resolved "https://registry.yarnpkg.com/@ember/test-helpers/-/test-helpers-2.6.0.tgz#d687515c6ab49ba72717fc62046970ef4a72ea9c"
+  integrity sha512-N5sr3layWk60wB3maCy+/5hFHQRcTh8aqxcZTSs3Od9QkuHdWBtRgMGLP/35mXpJlgWuu3xqLpt6u3dGHc8gCg==
   dependencies:
     "@ember/test-waiters" "^3.0.0"
     broccoli-debug "^0.6.5"