chore: Export codegen parseFile function (#35000)

Summary:
This PR export the content of the `parseFile` into a parseFile function accepting a callback to buildSchema properly in `parsers/utils.js` as requested on https://github.com/facebook/react-native/issues/34872.

## Changelog

[Internal] [Changed] - Export ` parseFile` in to a `parseFile` function in `parsers/utils.js`

Pull Request resolved: https://github.com/facebook/react-native/pull/35000

Test Plan:
Run `yarn jest react-native-codegen` and ensure CI is green

![image](https://user-images.githubusercontent.com/11707729/196051689-1b61838c-477c-4be5-8df0-9f5969fcf90d.png)

Reviewed By: cortinico

Differential Revision: D40424857

Pulled By: cipolleschi

fbshipit-source-id: a700033d674b8be8e1af942dedf73155ea3ca025