[BUG] Cannot work with @material-ui/core@next

[Jack-Works]

Bug Report Quick Checklist

• [x] I am on the latest version of Snowpack & all plugins.
• [x] I use package manager pnpm
• [x] I run Snowpack on OS Windows
• [x] I run Snowpack on Node.js v12+

Describe the bug

A quick, clear, concise summary of what the bug is.

To Reproduce

We can't fix bugs that we can't see for ourselves. Issues often need to be closed if this section is skipped.

1. pnpx -y create-snowpack-app --template @snowpack/app-template-react-typescript --target snowpack-test --use-pnpm
2. cd snowpack-test
3. pnpm i @emotion/styled@11 @material-ui/core@next @emotion/react@11
4. pnpm start
5. Change App.tsx to

import React from 'react';
import { Button } from '@material-ui/core';
export default () => <Button />;

6. See error!

Error: Package "object-assign" not found. Have you installed it? [12:47:08] [snowpack] [500] /_snowpack/pkg/react.v17.0.2/common/index-3563e646.js

Error: Package "@material-ui/utils" not found. Have you installed it? [12:50:45] [snowpack] [500] /_snowpack/pkg/@material-ui/unstyled.v5.0.0-alpha.29/common/index-0390184d.js

Error: Package "clsx" not found. Have you installed it? [12:50:45] [snowpack] [500] /_snowpack/pkg/@material-ui/unstyled.v5.0.0-alpha.29/common/_clsx_commonjs-external-a76593ca.js

If I install them manually...

7. pnpm i @material-ui/utils@next object-assign clsx
8. pnpm start (runtime error!)

Uncaught SyntaxError: The requested module '/_snowpack/pkg/@material-ui.unstyled.SliderUnstyled.v5.0.0-alpha.29.js' does not provide an export named 'getSliderUtilityClass'

[drwpow]

Duplicate of #3124?