NEW YORK — A string of missteps that included leaving detainees locked in their cells as a smoky fire raged around them were outlined in a city Board of Correction report released Friday about a near-deadly blaze in a Rikers Island jail. One detainee was severely burned and several others suffered serious smoke inhalation in the April 6 fire, which the Board of Correction report confirmed was sparked by a detainee angry over losing his shoes and some other personal possessions during a search by Correction Department Emergency Service officers. The Board of Correction’s findings confirm much o…