Add dependency that was accidentally removed

Author: dlarocque

packages/messaging/package.json

@@ -66,6 +66,7 @@
     "@firebase/app": "0.10.6",
     "rollup": "2.79.1",
     "rollup-plugin-typescript2": "0.31.2",
+    "@rollup/plugin-json": "4.1.0",
     "ts-essentials": "9.3.0",
     "typescript": "4.7.4"
   },