LONDON (Reuters) – British Prime Minister Boris Johnson told Ukrainian President Volodymyr Zelenskiy on Saturday that international partners were working intensively to find ways to resume the export of grain from Ukraine to avert a global food crisis. Johnson, who has spoken regularly to Zelenskiy since the beginning of the invasion, said the two leaders also discussed the importance of the international community remaining united over the war. “He said that the UK would work with G7 partners to push for urgent progress,” a British readout of the call said, on the export of grain. “The leader…