JUBA, South Sudan — Sudanese authorities have arrested two priests of the Coptic Orthodox Church in Sudan and accused them of baptizing a convert from Islam, sources said. Sudanese security forces on Dec. 16 arrested Markus Anthony, a Sudanese citizen of Egyptian origin based in El-Haj Yousif in northern Khartoum, and Sarbion Hussein of the Moro tribe in the Nuba…