Bump the development-dependencies group in /backend with 2 updates

Bumps the development-dependencies group in /backend with 2 updates: [@types/express](https://github.com/DefinitelyTyped/DefinitelyTyped/tree/HEAD/types/express) and [typescript-eslint](https://github.com/typescript-eslint/typescript-eslint/tree/HEAD/packages/typescript-eslint).


Updates `@types/express` from 4.17.21 to 5.0.0
- [Release notes](https://github.com/DefinitelyTyped/DefinitelyTyped/releases)
- [Commits](https://github.com/DefinitelyTyped/DefinitelyTyped/commits/HEAD/types/express)

Updates `typescript-eslint` from 8.17.0 to 8.18.0
- [Release notes](https://github.com/typescript-eslint/typescript-eslint/releases)
- [Changelog](https://github.com/typescript-eslint/typescript-eslint/blob/main/packages/typescript-eslint/CHANGELOG.md)
- [Commits](https://github.com/typescript-eslint/typescript-eslint/commits/v8.18.0/packages/typescript-eslint)

---
updated-dependencies:
- dependency-name: "@types/express"
  dependency-type: direct:development
  update-type: version-update:semver-major
  dependency-group: development-dependencies
- dependency-name: typescript-eslint
  dependency-type: direct:development
  update-type: version-update:semver-minor
  dependency-group: development-dependencies
...

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

backend/package.json

@@ -33,13 +33,13 @@
     "@types/bunyan": "^1.8.11",
     "@types/cors": "^2.8.17",
     "@types/eventsource": "^1.1.15",
-    "@types/express": "^4.17.21",
+    "@types/express": "^5.0.0",
     "eslint": "9.16",
     "globals": "^15.13.0",
     "ts-jest": "^29.2.5",
     "tsx": "^4.19.2",
     "typescript": "^5.7.2",
-    "typescript-eslint": "^8.17.0"
+    "typescript-eslint": "^8.18.0"
   },
   "engines": {
     "node": ">=18.0.0"