By Aidan Lewis and Farah Saafan CAIRO (Reuters) – After nine years of sweeping crackdowns on dissent, Egypt is set to launch a carefully choreographed political dialogue, but the main Islamist opposition movement is excluded and critics say a parallel move to release prisoners is proceeding too slowly. The dialogue, announced by President Abdel Fattah al-Sisi in April and expected to start in the coming weeks, will include some moderate opposition factions pushed to the margins since Sisi, while armed forces chief, led the 2013 ouster of Muslim Brotherhood President Mohamed Mursi after mass un…