[material-ui] Duplicate class names for components

[xettri]

Steps to reproduce

MUI-5

I've noticed duplicate class names being added to components, such as MuiButton-root, MuiButton-contained, MuiButton-containedPrimary, MuiButton-sizeMedium, MuiButton-containedSizeMedium and MuiButton-colorPrimary. This duplication occurs within the HTML elements, like the button example below. I'm unsure whether this is a bug or expected behavior. Can you clarify whether this duplication is intentional?
Similar we can see in almost all component like Checkbox, Select etc

<button
  class="MuiButtonBase-root MuiButton-root MuiButton-contained
    MuiButton-containedPrimary MuiButton-sizeMedium MuiButton-containedSizeMedium
    MuiButton-colorPrimary MuiButton-root MuiButton-contained MuiButton-containedPrimary
    MuiButton-sizeMedium MuiButton-containedSizeMedium
    MuiButton-colorPrimary css-1hw9j7s"
  tabindex="0"
  type="button"
>
  Contained<span class="MuiTouchRipple-root css-w0pj6f"></span>
</button>

Link to live example: This can be seen in MUI-5 doc pages as well
https://mui.com/material-ui/react-button/

Current behavior

Duplicates values of classes in html

Expected behavior

No duplicate values should be there (if they are not intentionally added)

Your environment

npx @mui/envinfo

  System:
    OS: macOS 13.1
  Binaries:
    Node: 16.20.0 - ~/.nvm/versions/node/v16.20.0/bin/node
    npm: 8.19.4 - ~/.nvm/versions/node/v16.20.0/bin/npm
    pnpm: 8.15.6 - ~/.nvm/versions/node/v16.20.0/bin/pnpm
  Browsers:
    Chrome: Not Found
    Edge: Not Found
    Safari: 16.2
  npmPackages:
    @types/react: ^18.2.47 => 18.2.65 
    typescript: ^5.3.3 => 5.4.2 

Search keywords: Duplicate class