update performance-exp package.json (#3842)

Author: Feiyang1

packages-exp/performance-exp/package.json

@@ -3,8 +3,9 @@
   "version": "0.0.800",
   "description": "Firebase performance for web",
   "author": "Firebase <[email protected]> (https://firebase.google.com/)",
+  "private": true,
   "main": "dist/index.cjs.js",
-  "browser": "dist/index.cjs.js",
+  "browser": "dist/index.esm.js",
   "module": "dist/index.esm.js",
   "esm2017": "dist/index.esm2017.js",
   "files": ["dist"],

packages-exp/performance-types-exp/package.json

@@ -3,6 +3,7 @@
   "version": "0.0.800",
   "description": "@firebase/performance Types",
   "author": "Firebase <[email protected]> (https://firebase.google.com/)",
+  "private": true,
   "license": "Apache-2.0",
   "scripts": {
     "test": "tsc",