Align 'No widgets available' text box properly in Widget picker. am: 260c38c4a0 am: d918a1a504 am: 713f53e5cb

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

Change-Id: I0f05e0345a5c8810468cb14a92fd940e3225da09