* Ugandan children drop out as schools hike fees * Government sued over failure to regulate charges * Lawyers say 'privatisation' fuels inequality By Hedwig Arinaitwe and Emma Batha KAMPALA, April 6 (Thomson Reuters Foundation) - Like many children in Uganda, Bridget Nabawanuka was excited about seeing her friends again after the world's longest pandemic school closure, but a steep hike in fees meant she never made it back to the classroom.