fix(bundle): use map_private_properties when configuring ReflectionExtractor

[nikophil]

configuration map_private_properties was not used to configure service automapper.property_info.reflection_extractor whereas without the bundle, \AutoMapper\Configuration::$mapPrivateProperties is actually used, this PR fixes this.

I had to introduce a way to have several configurations available for the fixture bundle, I'm using KernelTestCase::createKernel() + an additional config file path for this.

waiting for https://github.com/jolicode/automapper/pull/137