Fix UI prompt for new publicly scoped packages

[tommy-mitchell]

Fixes #660.

Needs test(s), but I'm not entirely sure how to test this.

[tommy-mitchell]

Related, maybe a CLI flag could be added to force this behavior? Something like --publish-scoped-public? Or perhaps just --access-public.

[tommy-mitchell]

If the user says no to publishing publicly, this could probably also catch the error from NPM about paying for private scoped packages and give a helpful message instead.

---

Edit - Added, but again needs tests:

// npm/handle-npm-error.js

const handleNpmError = (error, task, message, executor) => {
	// ...

	// Attempting to privately publish a scoped package without the correct npm plan
	// https://stackoverflow.com/a/44862841/10292952
	if (error.code === 402 || error.stderr.includes('npm ERR! 402 Payment Required')) {
		throw new Error('You cannot publish a privately scoped package without a paid plan. Did you mean to publish publicly?');
	}

	return throwError(error);
};

[sindresorhus]

I don't see how can test this without setting up a bunch of mocking or running a local npm server. Neither seem worth it.