A new report out by real estate company CBRE confirms the prevalence of a change that many firms are making in Chicago: shrinking offices.CBRE found in its latest report on Chicago law firm real estate trends that about 80 percent of Chicago’s spatially largest firms cut down on space in the past two years.“The takeaway is that this is something that is a fundamental change in how law firms do business and they’re going to continue to become more efficient and do everything they can to manage their costs …