PHILADELPHIA — The Delaware County District Attorney’s Office announced plans to investigate allegations that volunteer firefighters from the Briarcliffe Fire Company used racial slurs and disparaged Black residents in a late-January conversation following a virtual meeting. The investigation comes at the behest of Darby Township commissioners, who voted to suspend Briarcliffe Fire Company operations Wednesday after learning of a racist conversation, which included one Briarcliffe volunteer allegedly mocking the name of 8-year-old Fanta Bility — a Black child police officers fatally shot outsi…