Scripts: Ensure the default Prettier config is used with lint-js when needed

[gziolo]

Description

Follow-up for #20036.

wp-scripts lint-js uses the default Prettier settings if no config is provided in the root of the project. It wasn't the case for Gutenberg because it has Prettier config for IDE integration.

This patch adds a fallback for projects who opt-out from defining their own Prettier config and reuses the default one used with wp-scripts format-js

How has this been tested?

I removed ESLint config and Prettier config from the root level of Gutenberg and executed:
npm run lint-js

There were 24 errors reported but they are silenced with the existing ESLint plugin. That confirms that this patch works as intended.

Checklist:

• My code is tested.
• My code follows the WordPress code style.
• My code follows the accessibility standards.
• My code has proper inline documentation.
• I've included developer documentation if appropriate.
• I've updated all React Native files affected by any refactorings/renamings in this PR.