[code-infra] a few fixes uncovered during ESM updates

[Janpot]

Issues uncovered in #43264.

• replace .d.ts files without corresponding .js file with .ts files. When resolving to the final path in .d.ts these can't find a souce file otherwise.
• ☝️ uncovered an issue with missing types for LoadingButton. It's now exporting ButtonClassKey instead of LoadingButtonClassKey, etc... But the labs package tries to import those interfaces. I just alias them to fix this.
• Use api.env() in babel config instead of reading the env var directly
• Remove conflicting usage of both data-grid and data-grid-pro theme augmentation. It's one or the other.
• Support for import('') in types and dynamic import when resolving extensions
• Correct import from @mui/material/* inside of the @mui/material package
• Export a few types that were referenced but not exported
• Correct mui-types alias, it doesn't have a src folder

Edit:
closes #45072

[mui-bot]

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[DiegoAndai]

LGTM ✅

[github-actions]

Cherry-pick PRs will be created targeting branches: v6.x