[material-ui][Button] - Button doesn't have the loading props about material-ui

[mnajdova]

The LoadingButton will be moved to @mui/material in the next major version, we want new components to live in the lab so that we can experiment and collect feedback before promoting them as stable. @DiegoAndai typically in major versions we were moving the lab components to the @mui/mateiral package. Would it make sense to include this effort for v6? I think we can move the LoadingButton and the Timeline* components

Reduces Dependencies: Avoid the need for installing the @mui/lab package just for the loading button functionality.

See the above section for why we do this

Improves User Experience: Provides a straightforward way to manage loading states for buttons, improving the developer experience.

It was intentional that this is a new component so that we don't increase the bundle for the button component for this specific use-case