build: remove serialize script and @ngtool/json-schema deps

Wasnt needed or used.

Author: hansl

package.json

@@ -87,7 +87,6 @@
     "@bazel/jasmine": "~0.26.0",
     "@bazel/karma": "~0.26.0",
     "@bazel/typescript": "~0.26.0",
-    "@ngtools/json-schema": "^1.1.0",
     "@types/browserslist": "^4.4.0",
     "@types/caniuse-lite": "^1.0.0",
     "@types/copy-webpack-plugin": "^4.4.1",