fix: FirebaseFunctions/Backend/package.json to reduce vulnerabilities

The following vulnerabilities are fixed with an upgrade:
- https://snyk.io/vuln/SNYK-JS-GRPCGRPCJS-7242922

Author: snyk-io[bot]

FirebaseFunctions/Backend/package.json

@@ -2,7 +2,7 @@
   "name": "functions",
   "description": "Cloud Functions for Firebase",
   "dependencies": {
-    "firebase-admin": "^9.2.0",
+    "firebase-admin": "^13.0.0",
     "firebase-functions": "^3.0.0"
   },
   "private": true,