LPS-38678 - Nav items items can be dragged outside of nav bar

Hey @natecavanaugh,

Attached is an update for http://issues.liferay.com/browse/LPS-38678.

NOTE: This bug started when the structure of the classic theme navigation.vm was changed. Which shows that we should in fact support passing in a custom selector like we do for the list items, due to the fact that it breaks easily when the structure is changed slightly.

Please let me know if you have any questions.  Thanks!