title: Material UI TS1128: Declaration or statement expected for ButtonUnstyledProps
body: <p>I have run into a problem when trying to build my application that is utilizing Material UI. I'm getting this Typescript error, and can't seem to find an answer regarding this problem</p>
  <pre><code>TypeScript error in C:/.../node_modules/@mui/base/ButtonUnstyled/index.d.ts(3,1):
  Declaration or statement expected.  TS1128
  
      1 | export { default } from './ButtonUnstyled';
      2 | export { default as buttonUnstyledClasses, getButtonUnstyledUtilityClass, } from './buttonUnstyledClasses';
    &gt; 3 | export type { default as ButtonUnstyledProps } from './ButtonUnstyledProps';
        | ^
      4 | export * from './ButtonUnstyledProps';
      5 | export { default as useButton } from './useButton';
      6 | export type { default as UseButtonProps } from './UseButtonProps';
  
  </code></pre>
  <p>I stumbled upon a similar problem for a different component from MUI and upgrading React to 16.14.0 fixed the problem, but has not fixed this one.</p>