Explicitly bind the calculated implicit height to the flickable contentHeight
Items that can change dinamically their size won't play well with the auto-created flickable of a SvrollView, as in that case the flickable's contentHeight needs to be explicitly binded.
Do it after we are sure there is a flickable in the ScrollView as we don't want to trigger an early creation of the internal flickable as the client code might be wanting to assign a custom created flickable or item view