Re-apply: #21671 by @42shadow42

What I did

Enabled support for loading truly raw mjs,jsx, and tsx files by disabling the babel-loader when the raw query is set.

How to test

1. Run a sandbox for template, e.g. yarn task --task sandbox --template react-webpack/18-ts
2. Open Storybook in your browser
3. Comment the webpackFinal overrides in .storybook/main.ts
4. Access ?path=/docs/addons-docs-stories-mdx-raw-source--docs
5. Verify you see:

import React, { Fragment } from 'react';

export const MY_VALUE_I_WANT_TO_SHOW_IN_STORY = 'Hello World!';

export const RawSource = () => {
  return <Fragment>{MY_VALUE_I_WANT_TO_SHOW_IN_STORY}</Fragment>;
};

Instead of:

import React, { Fragment } from "react";
export const MY_VALUE_I_WANT_TO_SHOW_IN_STORY = "Hello World!";
export const RawSource = () => {
  return /* @__PURE__ */ React.createElement(Fragment, null, MY_VALUE_I_WANT_TO_SHOW_IN_STORY);
};

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"]

🦋 Canary release

This PR does not have a canary release associated. You can request a canary release of this pull request by mentioning the @storybookjs/core team here.

core team members can create a canary release here or locally with gh workflow run --repo storybookjs/storybook canary-release-pr.yml --field pr=<PR_NUMBER>