[core] Add react-next workflow in CircleCI

[cherniavskii]

Allows running MUI X tests against various React versions.

I've added a new react-next workflow that won't run unless approved manually in CircleCI - see https://github.com/cherniavskii/mui-x/blob/react-19-in-CI/test/README.md#next-version

[mui-bot]

Deploy preview: https://deploy-preview-13360--material-ui-x.netlify.app/

Generated by 🚫 dangerJS against f5689b7

[github-actions]

This pull request has conflicts, please resolve those before we can evaluate the pull request.

[LukasTy]

Very nice effort! 👏
Leaving a few notes.
Also, there seems to be an issue with one test on react-19.

[LukasTy]

Is it only this entry that warranted the need to duplicate this file instead of using the one from monorepo? 🤔
Is it necessary though? 🤔

[cherniavskii]

That's one of the reasons.
Another one was that I wasn't sure if the workspace root would be resolved correctly if using the file from the monorepo: https://github.com/mui/material-ui/blob/f993fe56f59d80c9b255c0585b6b428689dfea18/scripts/useReactVersion.mjs#L15
I'll give it a try

[LukasTy]

Another one was that I wasn't sure if the workspace root would be resolved correctly if using the file from the monorepo: https://github.com/mui/material-ui/blob/f993fe56f59d80c9b255c0585b6b428689dfea18/scripts/useReactVersion.mjs#L15

That script will definitely return the monorepo root.
That was the main reason why the yarn deduplicate script didn't work on mui-x. 🙈
https://github.com/mui/material-ui/blob/v5.13.5/scripts/deduplicate.mjs