Remove the "roave/better-reflection" dependency

[leofeyer]

Apparently, we no longer use the package, so this could also be a bugfix for Contao 5.2.

[ausi]

Looks like I added this in #4120 by mistake?

Did you check if vendor/bin/phpunit --extensions Contao\\CoreBundle\\Tests\\PhpunitExtension\\GlobalStateWatcher still works?

[ausi]

It was only needed for PHP versions lower than 8.1, see

contao/test-case/src/ContaoTestCase.php

Lines 333 to 336 in 89368ce

	// See https://github.com/php/php-src/commit/3eb97a456648c739533d92c81102cb919eab01c9
	if (\PHP_VERSION_ID >= 80100) {
	return [$property->hasDefaultValue(), $property->getDefaultValue()];
	}

So this can be removed, yes 👍