Bump mongodb from 6.14.2 to 6.20.0 in /frontend

Bumps [mongodb](https://github.com/mongodb/node-mongodb-native) from 6.14.2 to 6.20.0.
- [Release notes](https://github.com/mongodb/node-mongodb-native/releases)
- [Changelog](https://github.com/mongodb/node-mongodb-native/blob/main/HISTORY.md)
- [Commits](mongodb/node-mongodb-native@v6.14.2...v6.20.0)

---
updated-dependencies:
- dependency-name: mongodb
  dependency-version: 6.20.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]

frontend/package-lock.json

@@ -21,7 +21,7 @@
     "dompurify": "^3.2.3",
     "isomorphic-dompurify": "^2.22.0",
     "jsdom": "^26.0.0",
-    "mongodb": "^6.14.2",
+    "mongodb": "^6.20.0",
     "next": "15.1.7",
     "pino": "^9.11.0",
     "pino-pretty": "^13.1.1",