[ntuple] use new RResult::Unwrap function for descriptor builders
[ntuple] use new RResult::Unwrap function for descriptor builders

root-mirror/root,olifre/root,olifre/root,karies/root,olifre/root,root-mirror/root,root-mirror/root,root-mirror/root,karies/root,root-mirror/root,olifre/root,karies/root,olifre/root,root-mirror/root,root-mirror/root,olifre/root,olifre/root,olifre/root,karies/root,root-mirror/root,karies/root,olifre/root,root-mirror/root,root-mirror/root,karies/root,root-mirror/root,karies/root,karies/root,karies/root,karies/root,olifre/root,olifre/root,karies/root