elementary widget: fix to trigger object signal emit properly.

This is more generic way to trigger signals for all derived classes of layout.

This fixes the dayselector item signal emit issue as well.

@fix T6981

src/lib/elementary/efl_ui_widget.c

@@ -5747,7 +5747,8 @@ EAPI void
 elm_widget_signal_emit(Eo *obj, const char *emission, const char *source)
 {
    ELM_WIDGET_CHECK(obj);
-   if (evas_object_smart_type_check(obj, "elm_layout"))
+
+   if (efl_isa(obj, EFL_UI_LAYOUT_OBJECT_CLASS))
      elm_layout_signal_emit(obj, emission, source);
    else if (evas_object_smart_type_check(obj, "elm_icon"))
      {