build(deps): bump posthog-js from 1.236.7 to 1.239.0 in /frontend

Bumps [posthog-js](https://github.com/PostHog/posthog-js) from 1.236.7 to 1.239.0.
- [Release notes](https://github.com/PostHog/posthog-js/releases)
- [Changelog](https://github.com/PostHog/posthog-js/blob/main/CHANGELOG.md)
- [Commits](PostHog/posthog-js@v1.236.7...v1.239.0)

---
updated-dependencies:
- dependency-name: posthog-js
  dependency-version: 1.239.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]

frontend/package.json

@@ -22,7 +22,7 @@
     "graphql": "^16.9.0",
     "html-to-image": "^1.11.13",
     "lodash": "^4.17.21",
-    "posthog-js": "^1.236.7",
+    "posthog-js": "^1.239.0",
     "react": "^18.3.1",
     "react-dom": "^18.3.1",
     "react-json-view": "^1.21.3",