elementary: ensure that the parent model is still alive when resolving future for fileselector.
This future where relying on the parent model being alive to work (efl_parent_get). For
that reason we should have been using efl_future_then with the parent Model as a measure
to make sure this is always the case.
Reviewed-by: Marcel Hollerbach <email@example.com>
Differential Revision: https://phab.enlightenment.org/D8500