By Jan Strupczewski BRUSSELS (Reuters) -European Union leaders may discuss the possibility of Ukrainian membership at an informal summit in March, a senior EU official said on Monday, adding the issue was important for Ukraine in discussions with Russia on ending the conflict. Ukrainian President Volodymyr Zelenskiy said on Monday that he had signed an official request for Ukraine to join the bloc. “I think one of the reasons that this is important for President Zelenskiy is also potentially in some of the discussions with Russia on a way out,” the official said referring to talks to end the c…