LPS-37719

Hey Julio,

this is a small API change that is necessary to the calendar SMDH and other then that it is beneficial everywhere. Because className - classPK pair is unique at db level and at lar file level as well, we do not need to get groupId to fetch the given reference element from the lar, it is necessary only when we have the className - UUID  pair.

I did not add tests because the existing ones already test this scenario. 

thanks,
Daniel