Marks disabled list item to be non-longClickable for accessibility

A disabled item is a separator which should not be long-clickable, and
also remove the code to auto assign enabled value for accessibility.
The enabled value should be determined by the application developers.

Bug: 149810256
Test: manually test on ListView and GridView
Change-Id: I51ceeae2fb9d469e02059aafaf19a1442ff5d1c1