Mayor Zohran Mamdani rolled through on a float while Gov. Kathy Hochul marched in Monday’s notoriously rowdy West Indian Day Parade — as revelers grumbled that the heightened security “damped” the party vibe. The pair of pols — both wearing “Honorary Grand Marshal” sashes — received clamorous welcomes as they made their way through Crown Heights, Brooklyn, as part of the 59th annual festival — hours after four people were stabbed along the route.