fix(@schematics/angular): remove ngcc postinstall hook

Partially addresses #16017

Author: filipesilva

packages/schematics/angular/workspace/files/package.json.template

@@ -7,8 +7,7 @@
     "build": "ng build",
     "test": "ng test",
     "lint": "ng lint",
-    "e2e": "ng e2e",
-    "postinstall": "ngcc --properties es2015 browser module main --first-only --create-ivy-entry-points"
+    "e2e": "ng e2e"
   },
   "private": true,
   "dependencies": {