Add browser field to messaging

Author: hsubox76

packages-exp/messaging-compat/package.json

@@ -6,6 +6,7 @@
   "private": true,
   "author": "Firebase <[email protected]> (https://firebase.google.com/)",
   "main": "dist/index.cjs.js",
+  "browser": "dist/index.esm.js",
   "module": "dist/index.esm.js",
   "esm2017": "dist/index.esm2017.js",
   "typings": "dist/src/index.d.ts",

packages-exp/messaging-exp/package.json

@@ -5,6 +5,7 @@
   "description": "",
   "author": "Firebase <[email protected]> (https://firebase.google.com/)",
   "main": "dist/index.cjs.js",
+  "browser": "dist/index.esm.js",
   "module": "dist/index.esm.js",
   "esm2017": "dist/index.esm2017.js",
   "typings": "dist/index.d.ts",