fix: retain system data on structural_simplify of SDESystem

Author: AayushSabharwal

src/systems/systems.jl

@@ -154,8 +154,9 @@ function __structural_simplify(sys::AbstractSystem, io = nothing; simplify = fal
         end
 
         noise_eqs = StructuralTransformations.tearing_substitute_expr(ode_sys, noise_eqs)
-        return SDESystem(full_equations(ode_sys), noise_eqs,
+        return SDESystem(Vector{Equation}(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),
+            parameter_dependencies = parameter_dependencies(sys))
     end
 end