fix: angular - remove main entrypoint

Author: dmengelt

src/button-angular/package-template.json

@@ -2,7 +2,6 @@
   "name": "@google-pay/button-angular",
   "version": "0.0.0",
   "description": "Angular component for Google Pay button",
-  "main": "dist/index.js",
   "repository": {
     "type": "git",
     "url": "https://github.com/google-pay/google-pay-button",