refactor: pass in defaults in transform_pde_system!

Author: Sathvik Bhagavan

src/system_parsing/pde_system_transformation.jl

@@ -31,7 +31,7 @@ function PDEBase.transform_pde_system!(
         end
     end
 
-    sys = PDESystem(eqs, bcs, sys.domain, sys.ivs, Num.(v.ū), sys.ps, name = sys.name)
+    sys = PDESystem(eqs, bcs, sys.domain, sys.ivs, Num.(v.ū), sys.ps, name = sys.name, defaults = sys.defaults)
     return sys
 end