Bound drop target layout values to left and right. am: 3c0f4c15 am: f35388c9 am: 38353060

Original change: https://googleplex-android-review.googlesource.com/c/platform/packages/apps/Launcher3/+/18491881



Change-Id: Idb4c3eb6c296d9007c4fb3502abeacbcc9a62990
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>