Bump mongoose from 8.9.0 to 8.9.4 in /server

Bumps [mongoose](https://github.com/Automattic/mongoose) from 8.9.0 to 8.9.4.
- [Release notes](https://github.com/Automattic/mongoose/releases)
- [Changelog](https://github.com/Automattic/mongoose/blob/master/CHANGELOG.md)
- [Commits](https://github.com/Automattic/mongoose/compare/8.9.0...8.9.4)

---
updated-dependencies:
- dependency-name: mongoose
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

server/package.json

@@ -16,7 +16,7 @@
     "express": "^4.21.2",
     "joi": "^17.13.3",
     "jsonwebtoken": "^9.0.2",
-    "mongoose": "^8.9.0"
+    "mongoose": "^8.9.4"
   },
   "devDependencies": {
     "@types/bcrypt": "^5.0.2",