Fix: memory leak when using node tool in mesh edit mode

Caused by b40a9ce60b.

For the non-edit mode code path, the mesh is freed as part of
`BKE_mesh_nomain_to_mesh`.

source/blender/editors/geometry/node_group_operator.cc

@@ -226,6 +226,7 @@ static void store_result_geometry(
         if (object.mode == OB_MODE_EDIT) {
           EDBM_mesh_make_from_mesh(&object, new_mesh, scene.toolsettings->selectmode, true);
           BKE_editmesh_looptris_and_normals_calc(mesh.edit_mesh);
+          BKE_id_free(nullptr, new_mesh);
         }
         else {
           BKE_mesh_nomain_to_mesh(new_mesh, &mesh, &object);