Merge "Fix CellLayout cast exception when drag is canceled" into sc-dev am: 76f5572648 am: c13b47f7bf am: 745ec6050b

Original change: https://googleplex-android-review.googlesource.com/c/platform/packages/apps/Launcher3/+/14948453

Change-Id: I76e0085bf41271c3cdaeb2ae97160e7a388f6d00