Fix locale reorder jank

Using RecyclerView.ItemAnimator.ItemAnimatorFinishedListener
to only update the locales when all the animations finished.
This also reduces the number of repeated updates if the
locale list did not actually changed.

This was tested by setting the duration of animations to 3 seconds,
which made it possible to "shuffle" the list a lot and see several
items slowly moving around in the same time.

Bug: 26710681
Change-Id: I7d025e60cc252f4b90006b7b18c86d93ab94826f