[Workflow] Remove constraints on transition/place name

Transition/place names no longer apply this:

```diff
-        if (!preg_match('{^[\w_-]+$}', $place)) {
-            throw new InvalidArgumentException(sprintf('The place "%s" contains invalid characters.', $place));
-        }
```

See https://github.com/symfony/symfony/pull/26079. Review if we mention this in any place of the docs.