chore: S2 storybook standardisation updates, treeview generics fix (#8397)
* chore: TS explicit module S2
* fix any types in story
* accidentally checked in tsconfig
* tidy up
* fix types for s2 TreeView
* make two implementations align
* fix types again
* add pure
* fix lint
* undo changes to source
* undo tsconfig change
* fix story