Bump @vscode/test-electron from 2.3.8 to 2.3.9 in /client (#370)

Bumps [@vscode/test-electron](https://github.com/Microsoft/vscode-test) from 2.3.8 to 2.3.9.
- [Changelog](https://github.com/microsoft/vscode-test/blob/main/CHANGELOG.md)
- [Commits](https://github.com/Microsoft/vscode-test/commits/v2.3.9)

---
updated-dependencies:
- dependency-name: "@vscode/test-electron"
  dependency-type: direct:development
  update-type: version-update:semver-patch
...

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

Author: dependabot[bot]

client/package-lock.json

@@ -19,7 +19,7 @@
     "devDependencies": {
         "@types/glob": "^8.1.0",
         "@types/vscode": "1.86.0",
-        "@vscode/test-electron": "^2.3.8",
+        "@vscode/test-electron": "^2.3.9",
         "mocha": "^10.2.0"
     },
     "dependencies": {