chore(deps-dev): bump jest and @types/jest in /backend

Bumps [jest](https://github.com/jestjs/jest/tree/HEAD/packages/jest) and [@types/jest](https://github.com/DefinitelyTyped/DefinitelyTyped/tree/HEAD/types/jest). These dependencies needed to be updated together.

Updates `jest` from 29.7.0 to 30.4.2
- [Release notes](https://github.com/jestjs/jest/releases)
- [Changelog](https://github.com/jestjs/jest/blob/main/CHANGELOG.md)
- [Commits](https://github.com/jestjs/jest/commits/v30.4.2/packages/jest)

Updates `@types/jest` from 29.5.14 to 30.0.0
- [Release notes](https://github.com/DefinitelyTyped/DefinitelyTyped/releases)
- [Commits](https://github.com/DefinitelyTyped/DefinitelyTyped/commits/HEAD/types/jest)

---
updated-dependencies:
- dependency-name: "@types/jest"
  dependency-version: 30.0.0
  dependency-type: direct:development
  update-type: version-update:semver-major
- dependency-name: jest
  dependency-version: 30.3.0
  dependency-type: direct:development
  update-type: version-update:semver-major
...

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

backend/package.json

@@ -39,7 +39,7 @@
     "@types/compression": "^1.7.5",
     "@types/cors": "^2.8.17",
     "@types/express": "^4.17.21",
-    "@types/jest": "^29.5.14",
+    "@types/jest": "^30.0.0",
     "@types/jsonwebtoken": "^9.0.5",
     "@types/morgan": "^1.9.9",
     "@types/node": "^20.10.5",
@@ -50,7 +50,7 @@
     "@types/supertest": "^7.2.0",
     "eslint": "^9.39.4",
     "eslint-plugin-security": "^4.0.0",
-    "jest": "^29.7.0",
+    "jest": "^30.4.2",
     "nodemon": "^3.0.2",
     "supertest": "^7.2.2",
     "ts-jest": "^29.4.9",