Fix #106802: Incorrect modifier deform evaluation result

Since the positions of the final mesh are modified rather than a
separate array after d20f992, the final mesh has
to become the deformed mesh after the deform modifiers, rather
than the input mesh. The arrays can't be shared anymore, but that
performance loss will be solved by implicit sharing shortly.

source/blender/blenkernel/intern/DerivedMesh.cc

@@ -699,7 +699,7 @@ static void mesh_calc_modifiers(struct Depsgraph *depsgraph,
      * places that wish to use the original mesh but with deformed
      * coordinates (like vertex paint). */
     if (r_deform) {
-      mesh_deform = BKE_mesh_copy_for_eval(mesh_input, true);
+      mesh_deform = BKE_mesh_copy_for_eval(mesh_final, false);
     }
   }