Align 'No widgets available' text box properly in Widget picker. am: 260c38c4a0 am: d918a1a504

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

Change-Id: Ie2bfefee5f1dd205f853356adcdc6266c1548f3b