leanback: use item multiple align info when calculating scroll max

This wasn't discovered because the FullWidthDetails row was always tested
with related rows and it was never used to calculate scroll max.
If there is no row after FullWidthDetails row,  we need use the
last focusable view (the details descritpion)  to calcualte the scroll

Bug 24801632

Change-Id: Ia3345fbee2c81464a1b016c74b9c6561be551e9e
1 file changed