chore(deps): update dependency @testing-library/jest-dom to v7

Author: renovate[bot]

frontend/package-lock.json

@@ -48,7 +48,7 @@
   "devDependencies": {
     "@babel/core": "7.29.7",
     "@next/eslint-plugin-next": "^15.5.14",
-    "@testing-library/jest-dom": "^6.4.2",
+    "@testing-library/jest-dom": "^7.0.0",
     "@testing-library/react": "^16.0.0",
     "@types/jest": "^30.0.0",
     "@types/luxon": "^3.0.0",