NEW YORK — Five residents at a city-run migrant shelter on Randalls Island have been charged in connection with the stabbing of another resident, police said Friday. Another 12 residents were issued summonses, but the attacker who actually stabbed the 24-year-old victim is still being sought, according to cops. A security guard who was initially suspected of the stabbing has been cleared, police sources said. The victim, stabbed in the neck, is recovering at Harlem Hospital. The incident happened 3:25 p.m., with two groups squaring off against each other before the fight spilled outside. Polic…