Fix release scripts to check npm packages (#49788)

Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/49788

Release of 0.78 was successful but it failed to verify the package of NPM because of some error in the JS files.

Preparing for 0.79, I discovered some other issues in the NPM checking scripts.

This change should fix them.

## Changelog:
[Internal] - Fix publishing scripts

Reviewed By: fabriziocucci

Differential Revision: D70489717

fbshipit-source-id: 02a37d9a86fe108c7f7d2d634b8c0727dabb153d