The --from-panel option should also apply to GtkWidget::delete-event

Currently this option only applies when the xfce4-panel-profiles dialog is closed via the close button. It should also apply when the dialog is closed via the cross in the window decoration or by pressing the Esc key, i.e. on GtkWidget::delete-event.

Related: !1 (merged), xfce/xfce4-panel!1 (merged)