Prevent casting when chaining from deserialize

[maxveldink]

Currently, when you deserialize into a struct, we need to do casting if we use the result in a chain:

CreateEntityRequest
  .deserialize_from(:hash, entity_params.to_h)
  .and_then { |create_entity_request| CreateEntity.call(T.cast(create_entity_request, CreateEntityRequest)) }

This is because the deserialize result payload is a T::Struct but we can't guarantee the type. We should be able to fix this with a Tapioca compiler that adds more specific RBIs for each T::Struct present in your application.