As President Trump arrived in France on Monday just hours after taking in a series of cage fights outside the White House, U.S. allies will watch to see whether he approaches the annual Group of 7 summit there as an opportunity for collaboration or yet another brawl. Mr. Trump’s positions on trade, the war in Ukraine and NATO have put him at odds with European leaders for years. But it is the three-month U.S.-Israeli war with Iran that has pushed those allies to see Mr. Trump more as a