Forget the “Ho, ho, ho” this holiday season. It’s more like “ho-hum.” With consumer confidence sliding and unemployment levels unwavering, holiday sales will grow just 2.8% this year, down from 5.6% in 2010, according to a new study by Kantar Retail. Moreover, volume growth is forecast to be flat for the holiday and is at significant risk of turning negative by year-end or the start of 2012. “If unit volume or inflation-adjusted growth turns negative for r...