`g_file_enumerator_finalize` should not call `g_file_enumerator_close`
because object parts (i.e. subclass variable and/or resources) might
already be freed, causing memory safety issues.
A better place to call `g_file_enumerator_close` is
`g_file_enumerator_dispose` because it is safe to access the object
memory here.
Fixes#3713
Signed-off-by: fbrouille <150549-fbrouille@users.noreply.gitlab.gnome.org>