This PR was squashed before being merged into the 2.x branch.

Discussion
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[CI] Re-add PHP-CS-Fixer

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | no <!-- please update src/**/CHANGELOG.md files -->
| Docs?         | no <!-- required for new features -->
| Issues        | Fix #... <!-- prefix each issue number with "Fix #", no need to create an issue if none exist, explain below instead -->
| License       | MIT

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Follow #2802, #2074, #2014 and more.

I feel like Fabbot **only runs on modified files** for a given PR, but sometimes it does not really help (e.g.: if you untouched files contain old references to a deleted class).

This behavior is understandable for symfony/symfony, which contains a tons of code and is super active, but that's not the case symfony/ux, we have very less code and less activity.

**EDIT:** Well, I'm still not sure... PHP-CS-Fixer is showing me fixes for `src/LiveComponent/src/Util/TypeHelper.php`, added in #2778, but it was totally ignored by Fabbot... 😫

So, I suggest to re-add PHP-CS-Fixer run in the CI to ensure all files are correctly CS-fixed.

Commits
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1ab48b6 [CI] Re-add PHP-CS-Fixer