Build(deps): Bump @ember/test-helpers in /app/assets/javascripts (#22133)

Bumps [@ember/test-helpers](https://github.com/emberjs/ember-test-helpers) from 2.9.3 to 2.9.4.
- [Release notes](https://github.com/emberjs/ember-test-helpers/releases)
- [Changelog](https://github.com/emberjs/ember-test-helpers/blob/v2.9.4/CHANGELOG.md)
- [Commits](https://github.com/emberjs/ember-test-helpers/compare/v2.9.3...v2.9.4)

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

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

app/assets/javascripts/discourse/package.json

@@ -24,7 +24,7 @@
     "@ember/jquery": "^2.0.0",
     "@ember/legacy-built-in-components": "^0.4.2",
     "@ember/render-modifiers": "^2.1.0",
-    "@ember/test-helpers": "^2.9.3",
+    "@ember/test-helpers": "^2.9.4",
     "@glimmer/component": "^1.1.2",
     "@glimmer/syntax": "^0.84.3",
     "@glimmer/tracking": "^1.1.2",

app/assets/javascripts/yarn.lock

@@ -1164,10 +1164,10 @@
   dependencies:
     ember-cli-babel "^7.26.6"
 
-"@ember/test-helpers@^2.9.3":
-  version "2.9.3"
-  resolved "https://registry.yarnpkg.com/@ember/test-helpers/-/test-helpers-2.9.3.tgz#c2a9d6ab1c367af92cf1a334f97eb19b8e06e6e1"
-  integrity sha512-ejVg4Dj+G/6zyLvQsYOvmGiOLU6AS94tY4ClaO1E2oVvjjtVJIRmVLFN61I+DuyBg9hS3cFoPjQRTZB9MRIbxQ==
+"@ember/test-helpers@^2.9.4":
+  version "2.9.4"
+  resolved "https://registry.yarnpkg.com/@ember/test-helpers/-/test-helpers-2.9.4.tgz#985022e9ba05cfc918bcf08b77cbb355f85b723e"
+  integrity sha512-z+Qs1NYWyIVDmrY6WdmOS5mdG1lJ5CFfzh6dRhLfs9lq45deDaDrVNcaCYhnNeJZTvUBK2XR2SvPcZm0RloXdA==
   dependencies:
     "@ember/test-waiters" "^3.0.0"
     "@embroider/macros" "^1.10.0"