By MARC SANTORA Ukrainian President Volodymyr Zelenskyy removed his top general on Tuesday amid swelling public protests and growing concerns that the national unity that had helped the country survive nearly five years of war was in danger of fracturing. The dismissal of Gen. Oleksandr Syrskyi was a major reversal for Zelenskyy, who just days earlier sided with the general and fired Ukraine’s defense minister, Mykhailo Fedorov. Thousands of people had joined mass demonstrations to pressure…