fix: sdesystems don't have W_prototype

Author: vyudu

src/systems/diffeqs/sdesystem.jl

@@ -667,7 +667,6 @@ function DiffEqBase.SDEFunction{iip, specialize}(sys::SDESystem, dvs = unknowns(
         tgrad = _tgrad === nothing ? nothing : _tgrad,
         mass_matrix = _M,
         jac_prototype = W_prototype,
-        W_prototype = W_prototype,
         observed = observedfun,
         sparsity = sparsity ? jacobian_sparsity(sys) : nothing,
         analytic = analytic,