[CodingStyle] Remove MinMaxToClampRector from coding style level

[TomasVotruba]

MinMaxToClampRector already lives in the Rector\Php86\Rector\FuncCall namespace and is registered in config/set/php86.php, but it was still listed in the coding style level.

It is a PHP version feature rule (clamp() is new in PHP 8.6, the rule implements MinPhpVersionInterface), not a coding style one. This removes it from CodingStyleLevel so it only ships via the php86 set.

The rule itself is unchanged:

-$value = min(max($value, $min), $max);
+$value = clamp($value, $min, $max);