Merge "Check if ThumbnailData's bitmap is null in TaskThumbnailCache" into sc-v2-dev am: 39aceb6dc7 am: cf2f085d23

Original change: https://googleplex-android-review.googlesource.com/c/platform/packages/apps/Launcher3/+/16282756

Change-Id: I02a126667b4efd487354db335c9f82482d7e7d17