Merge "Add null check before detach content view from dragView at onDropComplete" into sc-dev am: 5b786ca88d am: 3a813de8e1 am: 2ca51002b9

Original change: https://googleplex-android-review.googlesource.com/c/platform/packages/apps/Launcher3/+/15042822

Change-Id: I9aa7c358c2c8c8635123851a55b61920952dc78d