Fix bug with composer-based command and Symfony configuration

[TomasVotruba]

Spotted in: #8246 (comment)

---

Adds symfony: true to withComposerBased() in rector.php, so rector-src is covered by the Symfony composer-bound rules.

Fix: fatal error in bin/rector composer-based

The Symfony composer-based.php set builds a UnionType via newInstanceWithoutConstructor() and only sets types, leaving $normalized uninitialized. Rendering the configuration table then crashed:

PHP Fatal error:  Uncaught Error: Typed property PHPStan\Type\UnionType::$normalized
must not be accessed before initialization in src/Console/Command/ComposerBasedCommand.php:205

 foreach ($reflectionObject->getProperties() as $reflectionProperty) {
+    // lazy-initialized property, e.g. PHPStan UnionType::$normalized
+    if (! $reflectionProperty->isInitialized($value)) {
+        continue;
+    }
+
     $printedPropertyValues[] = $this->printConfigurationValue($reflectionProperty->getValue($value));
 }