Merge "Add null check before detach content view from dragView at onDropComplete" into sc-dev am: 5b786ca88d am: 8ec3545fb2

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

Change-Id: I98d191aa4bfea42cb90b36dbf7875bd55c385c7c