So much for Zohran Mamdani’s ballyhooed anti-President Trump tour. The Democratic socialist on Tuesday again spent a stop on his weeklong “Five Boroughs Against Trump” tour instead bashing his mayoral election rival Andrew Cuomo — calling the pugilistic ex-gov “petty” amid their escalating spat over Mamdani’s $2,300 rent-stabilized apartment. Even when Mamdani spoke about Trump,…