chore: sync lockfile with widened firebase-admin peer range

The firebase-admin devDependency stays at ^12 because firebase-functions
^4.9.0 peer-requires ^10 || ^11 || ^12, so CI does not exercise v14 yet.

Author: IzaakGough

package-lock.json

@@ -52,7 +52,7 @@
     "chai": "^4.2.0",
     "eslint": "^8.57.1",
     "eslint-config-prettier": "^10.1.8",
-    "firebase-admin": "^14.3.0",
+    "firebase-admin": "^12.0.0",
     "firebase-functions": "^4.9.0",
     "firebase-tools": "^13.15.4",
     "mocha": "^11.7.6",