SystemUI: fix nav bar layout while toggling cursor keys with an IME up

Previously there was no option to have the IME up on that settings
screen so this was not a concern before; however, with the addition of
searchable settings, it seems users are now trying to toggle it with the
IME active, putting the nav bar in a strange state becuase it did not
restore the previous states properly.

Change-Id: Ib03ff3d9ee9679819eaa42644796e8f9eae6e694
Signed-off-by: Roman Birg <roman@cyngn.com>