UServerInstancedActorsSpawnerSubsystem::OnInstancedActorComponentInitialize

Called by [UInstancedActorsComponent::InitializeComponent](API\Plugins\InstancedActors\UInstancedActorsComponent\InitializeComponent) to provide an opportunity, before BeginPlay, to catch Instanced Actors we're spawning, to set their [FMassEntityHandle](API\Plugins\MassEntity\FMassEntityHandle) association.