Align 'No widgets available' text box properly in Widget picker. am: 260c38c4a0 am: 867be835aa

Original change: https://googleplex-android-review.googlesource.com/c/platform/packages/apps/Launcher3/+/14505876

Change-Id: Ieebf1feb92d44d216395952b494846fcd7c0d7d0