BHV-15359: List item shows incorrect result when it has an checkbox item and bind with model's selected property

### Issue:
Problems when you combine binding a model property to a checkbox, with using the selectionProperty attribute
### Fix:
when a control is assigned a model in generatePage(), add a check to synchronize the model property with the list's selections

Enyo-DCO-1.1-Signed-off-by: Krishna Rangarajan <krishna.rangarajan@lge.com>
Is there any issue with consolidating the logic without using a separate method, changing this line to:

    var s = list.selectionProperty;
    view.set('selected', s && view.model.get(s) && !list.isSelected(view.model));

I believe that the `list.select` method will effectively set the `selected` property of the control to `false`, before it is set back to `true` on this line, so that might be unnecessary. Is it desired that the observers be notified that the items are selected? This would be the main thing missing by not calling `list.select`, but I'm not sure if we actually want that in this case.