fix(deps): update dependency helmet to v8

Author: renovate[bot]

package.json

@@ -58,7 +58,7 @@
     "cors": "^2.8.5",
     "express": "^4.18.2",
     "firebase-admin": "^12.0.0",
-    "helmet": "^7.1.0",
+    "helmet": "^8.0.0",
     "mongodb": "^6.3.0",
     "pino": "^9.0.0",
     "pino-http": "^10.0.0"