[material-ui] Remove `enableColorScheme` prop from CssBaseline about material-ui

[siriwatknp]

I think we can remove it before the stable release of v6. It's a breaking change but I think CssBaseline is used once in a project.

[o-alexandrov]

@oliviertassinari thank you for linking the issue and specifying the point 4. Would you like to reword the 4th point there, so it says removal, instead of setting the value to true by default?

• if yes, then I’d happily suggest to close this issue as this one would become a duplicate

[oliviertassinari]

The prop was added to avoid breaking changes, as far as I remember.

This issue looks like point 4 of #38507 but where we also remove the prop.

[headironc]

I'll try completing this.

[chrisbellstardust]

There doesnt seem to be much documentation on actually removing props -- after starting this change I realized this isn't really just a code change and more may be needed.

• Should the existence of the prop from the css baseline component on the docs be removed?

This issue might be "fixed" faster if we just default the enableColorScheme to true and deprecate the prop?