FBI Steps Up ProbeBy Emilie Lounsberry, Mark Fazlollah and Clea BensonInquirer Staff Writers A wide-ranging federal investigation of alleged corruption in City Hall broke into the open yesterday, as FBI agents seized records from people with political ties to Mayor Street.In several searches across the city, federal agents rushed to preserve possible evidence the day after Philadelphia police found a listening device that the FBI had planted in the ceiling of Street's City Hall office.Yesterday morning, agents raided a small financial firm run by two Street supporters, including one of Philadelphia's most prominent Muslim leaders. Under Street's administration, the firm...