Merge "Send widget added and removed events to AiAi." into sc-v2-dev am: 29c3f23be5

Original change: https://googleplex-android-review.googlesource.com/c/platform/packages/apps/Launcher3/+/16006577

Change-Id: I4a572f1f79fbf3f82743495c808a9235f57cf0ca