Core: Disable esbuild on files imported from node_modules

[tmeasday]

Running esbuild over some of our larger imports (e.g. typescript, imported by react-docgen-typescript-plugin) can significantly increase their import time (not totally clear why as they are JS files).

I'm not sure why we changed this setting from the default (to not run esbuild over node_modules) in the first place.

What I did

Switched back to the default -- to leave files from node_modules untranspiled.

How to test

Hopefully should be covered by the daily sandboxes. But it would be very interesting to see how this affects our measured timings.

Checklist

• Make sure your changes are tested (stories and/or unit, integration, or end-to-end tests)
• Make sure to add/update documentation regarding your changes
• If you are deprecating/removing a feature, make sure to update
  MIGRATION.MD

Maintainers

• If this PR should be tested against many or all sandboxes,
  make sure to add the ci:merged or ci:daily GH label to it.
• Make sure this PR contains one of the labels below.

["cleanup", "BREAKING CHANGE", "feature request", "bug", "documentation", "maintenance", "dependencies", "other"]

[shilman]

This looks OK to me, but tbh I really don't understand the implications. I guess this will have problems with ESM-only packages until node supports ESM out of the box?

[ndelangen]

Node does support ESM out of the box starting node16 (which is the minimum for storybook already), as long as you import ESM with an imperative import. You can't require an ESM.

[shilman]

If we need to, we can add this as a config option to main.js later