[wpilibj] Fix RobotBase.isSimulation() (#5783)

#3534 changed it from returning !isReal() to checking against a numeric value, but #3565 (merged earlier) had changed the value to an enum.

wpilibj/src/main/java/edu/wpi/first/wpilibj/RobotBase.java

@@ -202,7 +202,7 @@ public abstract class RobotBase implements AutoCloseable {
    * @return If the robot is running in simulation.
    */
   public static boolean isSimulation() {
-    return HALUtil.getHALRuntimeType() != 0;
+    return getRuntimeType() == RuntimeType.kSimulation;
   }
 
   /**