We decided to always shift the cells down, so that the new row always
shows up at the top
Bug: 391697719
Test: GridMigrationTest
Flag: com.android.launcher3.one_grid_specs
Change-Id: Id093e0d64e437bf218f942bfdf6d2f14ee875776
For example going from 4x5 to 4x6 it will keep the 4x5 configuration
which fits in the 4x6 grid.
Also, it fixes GridMigrationTest which was flaky because of
how it sorted arrays.
Bug: 325286145
Flag: ACONFIG grid_migration_fix disabled
Test: NA
Change-Id: I6063e3c303320096f7429a3b1d909e107d2ef2a0