Merge "launcher: use scalable grid in 4x4" into sc-v2-dev am: 5f8bbcd552 am: e5b9e95161

Original change: https://googleplex-android-review.googlesource.com/c/platform/packages/apps/Launcher3/+/15754333

Change-Id: I569b24b60e99bd074e6471fe9337a452a79a76c1