Before this fix, only services explicitly configured with public=false were exposed via the test service container:
```
$container->register(PrivateService::class, PrivateService::class)->setPublic(false);
```
but not those explicitly configured as private:
```
$container->register(PrivateService::class, PrivateService::class)->setPrivate(true);
```
nor those implicitly configured as private:
```
$container->register(PrivateService::class, PrivateService::class);
```
