Use PHP7.4 property typehinting where possible

[vitormattos]

Background

I used rector to do this big refactor with this code on rector.php:

return static function (ContainerConfigurator $containerConfigurator): void {
	$parameters = $containerConfigurator->parameters();
	$parameters->set(Option::PATHS, [
		__DIR__ . '/lib',
		__DIR__ . '/tests/php',
	]);

	$parameters->set(Option::BOOTSTRAP_FILES, [
		__DIR__ . '/vendor/autoload.php',
		__DIR__ . '/../../lib/composer/autoload.php',
		__DIR__ . '/../../3rdparty/autoload.php',
	]);

	$parameters->set(Option::AUTO_IMPORT_NAMES, true);
	$parameters->set(Option::IMPORT_SHORT_CLASSES, false);

	$services = $containerConfigurator->services();
	$services->set(TypedPropertyRector::class)
		->configure([
			TypedPropertyRector::INLINE_PUBLIC => true,
		]);
};

I don't versioned this code (implementation of rector) because I think is very specific to do refactors, but is a good point to check if is necessary version.

Steps

• Fix the problems identified on PHPUnit.
• Fix phpcs issues
• Fix psalm issues 94c29af

Close #7079