fix: retain system data on structural_simplify of SDESystem

Author: AayushSabharwal

src/systems/systems.jl

@@ -156,6 +156,7 @@ function __structural_simplify(sys::AbstractSystem, io = nothing; simplify = fal
         noise_eqs = StructuralTransformations.tearing_substitute_expr(ode_sys, noise_eqs)
         return SDESystem(full_equations(ode_sys), noise_eqs,
             get_iv(ode_sys), unknowns(ode_sys), parameters(ode_sys);
-            name = nameof(ode_sys), is_scalar_noise, observed = observed(ode_sys))
+            name = nameof(ode_sys), is_scalar_noise, observed = observed(ode_sys), defaults = defaults(sys),
+            guesses = guesses(sys), initialization_eqs = initialization_equations(sys))
     end
 end