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

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

Change-Id: I80ec42a28eb10b2c3411108638db06a7ca40416c