Merge "Add border spacing and fixed cell height to grid." into sc-dev am: 8dd4ddc7ae

Original change: https://googleplex-android-review.googlesource.com/c/platform/packages/apps/Launcher3/+/13532637

MUST ONLY BE SUBMITTED BY AUTOMERGER

Change-Id: Icd3c31d4fdc87b60b12d8e81d3ffdbe10e451431