Consumers continued to pick up chicken nuggets, burgers and fries from McDonald’s despite concerns that higher gas prices from the war with Iran would translate into eating out less. Global sales at McDonald’s restaurants open at least a year rose 3.8% in the quarter that ended in March, compared with the same period last year, the company reported Thursday. In the United States, same-store sales grew 3.9% from a year earlier. Since the war with Iran began more than two months ago, investors and analysts have been increasingly concerned that consumers, particularly lower-income families, could cut back on their spending at restaurants. The average price of a gallon of regular unleaded gasoline rose 35% during March, according to the AAA auto club. But McDonald’s solid results in the quarter echoed what several other large restaurant chains reported over the past week.…