build_legacy_layout

With the new Dojo storage management (DojoStore trait), variants start from 1, while they were started from 0 in the legacy Dojo storage system. To still support legacy Dojo models, we have to rebuild the legacy storage layout from the new storage layout, meaning that variant selectors have to be decremented by one.

Fully qualified path: dojo::meta::layout::build_legacy_layout

pub fn build_legacy_layout(layout: Layout) -> Layout