MSNBC’s Mika Brzezinski punctuated a scathing analysis of Donald Trump’s election chances with a “sad trombone” sound effect. The presidential race has been upended since Joe Biden stepped aside and endorsed Kamala Harris, and Wisconsin Democratic Party chair Ben Wikler told “Morning Joe” the vice president’s ascendance took away Trump’s advantage against the 81-year-old president’s age — and made his own fitness a liability. “It’s like a flipped script,” Wikler said. “The Republican campaign for so long has been focused on this kind of propaganda campaign about physical attributes with these …