WASHINGTON — A deal between President Donald Trump and Congress to protect young immigrants from deportation remained distant Tuesday, as House Republicans leaders turned their attention to building support for a backup plan: a stopgap funding bill to stave off the threat of an election-year shutdown. The focus on a budget Plan B — another temporary measure that would buy time for more talks — was the latest sign of a breakdown in bipartisan deal-making in a Congress that has struggled to find common ground even on areas of broad agreement.