Merge "Add toast instructing user to select second split app" into sc-v2-dev am: 31e400d62e am: b1e429e011

Original change: https://googleplex-android-review.googlesource.com/c/platform/packages/apps/Launcher3/+/15925826

Change-Id: I6e3f4ee8f85ebbc19b6a9e2796215e1fa45408c6