Bill Maher urged viewers not to let President Donald Trump dampen their spirits ahead of the nation’s 250th birthday, arguing that no political side “owns being psyched about the country.” The comedian made the point during his “New Rule” segment for Friday’s “Real Time With Bill Maher,” where he took umbrage with those boycotting July 4th due to Trump being president. “Everybody has to start getting a little more excited for America’s birthday,…