Maybe update `LazyStack` so that this warning vanishes in Julia 1.9

[lgeissbauer-btig]

┌ LazyStack [1fad7336-0346-5a1a-a56f-a06ba010965b]
│  WARNING: Wrapping `Vararg` directly in UnionAll is deprecated (wrap the tuple instead).

[mcabbott]

Sorry, I think I fixed LazyStack but haven't yet updated the code here to use the latest version. (Or not to use it at all, perhaps.)