[wpimath] PIDController::Calculate(double, double): update setpoint flag (#5021)

Fixes #5020.

wpimath/src/main/java/edu/wpi/first/math/controller/PIDController.java

@@ -327,6 +327,7 @@ public class PIDController implements Sendable, AutoCloseable {
    */
   public double calculate(double measurement, double setpoint) {
     m_setpoint = setpoint;
+    m_haveSetpoint = true;
     return calculate(measurement);
   }