[C++] Reduce allocation in Substrait serde

[westonpace]

Describe the enhancement requested

Comment from review of #40696

You can use destination-passing style to avoid extra allocations with protobuf types:

    auto *user_defined = lit_->mutable_user_defined();
    user_defined->set_type_reference(anchor);
    value.PackTo(user_defined->mutable_value());

This will improve the performance of the Substrait serde

Component(s)

C++