leanback: fix alignment when appending to last item.

When append new item, it falls into fastRelayout() path
where LM didn't updateScrollMin/Max for the new item.

Bug: 32488200
Test: testAddLastItemHorizontal testAddMultipleLastItemsHorizontal
Change-Id: I660207a1fa48ff899e487b4ee457b57067ab4725
2 files changed