chore(deps): bump multer from 2.0.2 to 2.1.1 in /apps/backend

Bumps [multer](https://github.com/expressjs/multer) from 2.0.2 to 2.1.1.
- [Release notes](https://github.com/expressjs/multer/releases)
- [Changelog](https://github.com/expressjs/multer/blob/main/CHANGELOG.md)
- [Commits](expressjs/multer@v2.0.2...v2.1.1)

---
updated-dependencies:
- dependency-name: multer
  dependency-version: 2.1.1
  dependency-type: direct:production
...

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

Author: dependabot[bot]

apps/backend/package.json

@@ -48,7 +48,7 @@
     "esm": "^3.2.25",
     "express": "^5.2.1",
     "mongoose": "^9.0.1",
-    "multer": "2.0.2",
+    "multer": "2.1.1",
     "nanoid": "^5.1.6",
     "passport": "^0.7.0",
     "passport-github": "^1.1.0",