build(deps): bump openai from 6.19.0 to 6.21.0

Bumps [openai](https://github.com/openai/openai-node) from 6.19.0 to 6.21.0.
- [Release notes](https://github.com/openai/openai-node/releases)
- [Changelog](https://github.com/openai/openai-node/blob/master/CHANGELOG.md)
- [Commits](openai/openai-node@v6.19.0...v6.21.0)

---
updated-dependencies:
- dependency-name: openai
  dependency-version: 6.21.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]

packages/backend/package.json

@@ -120,7 +120,7 @@
     "isomorphic-git": "^1.36.3",
     "js-yaml": "^4.1.1",
     "mustache": "^4.2.0",
-    "openai": "^6.19.0",
+    "openai": "^6.21.0",
     "postman-code-generators": "^1.14.1",
     "postman-collection": "^5.2.1",
     "semver": "^7.7.4",