BUDAPEST, Hungary — Around 50 European leaders, including Ukrainian President Volodymyr Zelenskyy and NATO Secretary-General Mark Rutte, will be reassessing their trans-Atlantic relations in the hope that Donald Trump’s second U.S. presidency will avoid the strife and political pitfalls of his first administration. Further compounding an already complicated situation, Germany — Europe’s troubled economic juggernaut — sank into political crisis after German Chancellor Olaf Scholz fired his finance minister.