Feature: #86964 - Allow getting class property default value

See Issue #86964

Description

It is now possible to get the default value of a class property when using the TYPO3\CMS\Extbase\Reflection\ReflectionService.

class MyClass
{
    public $myProperty = 'foo';
}

$property = GeneralUtility::makeInstance(\TYPO3\CMS\Extbase\Reflection\ReflectionService::class)
    ->getClassSchema(MyClass::class)
    ->getProperty('myProperty');

$defaultValue = $property->getDefaultValue(); // "foo"