elementary: prevent asynchronous properties change to believe target is ready when it is not in fileselector.
In some case, the properties changed event would be triggered first on the object model
instead of the target model. This now enforce that the target will be the first model
to handle and react on the information.
Reviewed-by: Marcel Hollerbach <firstname.lastname@example.org>
Differential Revision: https://phab.enlightenment.org/D8449