chore(deps): bump express in /backend

Bumps [express](https://github.com/expressjs/express) to 4.22.1 and updates ancestor dependency . These dependencies need to be updated together.


Updates `express` from 4.21.2 to 4.22.1
- [Release notes](https://github.com/expressjs/express/releases)
- [Changelog](https://github.com/expressjs/express/blob/v4.22.1/History.md)
- [Commits](expressjs/express@4.21.2...v4.22.1)

Updates `express` from 5.1.0 to 5.2.1
- [Release notes](https://github.com/expressjs/express/releases)
- [Changelog](https://github.com/expressjs/express/blob/v4.22.1/History.md)
- [Commits](expressjs/express@4.21.2...v4.22.1)

---
updated-dependencies:
- dependency-name: express
  dependency-version: 4.22.1
  dependency-type: direct:production
- dependency-name: express
  dependency-version: 5.2.1
  dependency-type: indirect
...

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

Author: dependabot[bot]

backend/package-lock.json

@@ -23,7 +23,7 @@
     "dayjs": "^1.11.13",
     "dotenv": "^16.4.7",
     "eventsource": "^3.0.6",
-    "express": "^4.21.2",
+    "express": "^4.22.1",
     "express-mongo-sanitize": "^2.2.0",
     "express-rate-limit": "^7.5.0",
     "mongoose": "^8.13.2",