feature: allow to use Factory::create() and factory service in data providers

[nikophil]

fixes #532

Since sebastianbergmann/phpunit#5913, PHPUnit's extensions bootstrap() methods are called before data provider and since sebastianbergmann/phpunit#5917, data provider related events are dispatched synchronously (before this, they were deferred, which wasn't useful for us).

This now opens the door for cool things:

• we can boot Foundry "for kernel tests" before the data providers are called, allowing to use service factories in data providers
• we can now detect whether or not we are inside a data provider, and decide to return a proxy instead of actually calling create() in the data provider.

so, after this PR will be merged, all of these will be working:

final class SomeUnitTest extends TestCase
{
    #[DataProvider('provide')]
    public function testSomethingWithoutDB(SomeObject $object): void
    {
        // ...
    }

    public static function provide(): iterable
    {
        yield [SomeObjectFactory::createOne()];
        yield [SomePersistentObjectFactory::createOne()]; // won't try to store anything in db
        yield [SomePersistentProxyObjectFactory::createOne()]; // won't try to store anything in db
    }
}

final class SomeIntegrationTest extends KernelTestCase
{
    #[DataProvider('provide')]
    public function testSomethingWithDB(SomeObject $object): void
    {
        // ...
    }

    public static function provide(): iterable
    {
        yield [SomeProxyObjectPersistentFactory::createOne()];
        yield [SomeProxyObjectPersistentFactoryAsAService::createOne()]; 
    }
}

Since we need to return a proxy object, I decided that trying to call NotAProxyButStillPersistentFactory::create() inside a data provider will throw an error, but I'm open to change this.

Sadly, the feature will land in PHPUnit 11.4, which will be released in October. So, we have plenty of time to test it :)

---

Beside of this, the newly merged PR in PHPUnit, will allow to use the "in-memory" behavior in data providers, which was my last blocker for this awesome feature.

[kbond]

This is really nice! ❤️