Fix setupwizard for use_resource_processor: true

ResourceProcessorBusyBox doesn't generate the
R.styleable.SuwRecyclerItemAdapter_selectableItemBackground field
unless selectableItemBackground is added to attrs.xml.

Bug: 294256649
Test: m javac-check
Change-Id: I383b8136e41e2a09dd820743f84d193053faa437