v7: drop dead has_destats re-export; revert Hard DAE assertion#3479

ChrisRackauckas merged 1 commit intoSciML:v7SciML/OrdinaryDiffEq.jl:v7from

ChrisRackauckas-Claude:fix-v7-has-destats-and-hard-daeChrisRackauckas-Claude/OrdinaryDiffEq.jl:fix-v7-has-destats-and-hard-daeCopy head branch name to clipboard