A contentious new sales tax on services that Democratic state lawmakers relied on to pay for Washington’s latest budget is set to take effect Wednesday. Hundreds of millions of dollars will also flow to local governments, as they get a share of state sales tax proceeds. But a key piece of the new tax law is in question. Cable juggernaut Comcast believes the measure’s sales tax on advertising services is illegal and is suing to get it overturned. The law earns the state money by applying the retail sales tax to more services.