After a state consumer agency discovered Starbucks Coffee Co. was charging a hidden fee on bags of coffee beans and slapped it with a fine, the coffee giant is dropping the secret surcharge. Starbucks was adding about $1.50 to the price of bags of coffee beans weighing less than a pound, never posting the addition. The Massachusetts’ Office of Consumer Affairs and Business Regulation discovered the practice in late August and two weeks ago fined five Starbucks locations with $1,575 for overcharge violations.