Fix Lidar DrawDebugPoints causing crash

[rajat2004]

Make the points non-persistent and reduce Lifetime

Issue: #2608
FYI @IamPete1 @nightduck

Also see https://www.ue4community.wiki/Legacy/Draw_3D_Debug_Points,_Lines,_and_Spheres:_Visualize_Your_Algorithm_in_Action

For someone trying to reproduce-

{
    "SeeDocsAt": "https://github.com/Microsoft/AirSim/blob/master/docs/settings_json.md",
    "SettingsVersion": 1.2,
    "SimMode": "Multirotor",
     "Vehicles": {
        "Drone1": {
            "VehicleType": "simpleflight",
            "AutoCreate": true,
            "Sensors": {
                "LidarSensor1": { 
                    "SensorType": 6,
                    "Enabled" : true,
                    "NumberOfChannels": 16,
                    "RotationsPerSecond": 10,
                    "PointsPerSecond": 100000,
                    "X": 0, "Y": 0, "Z": -1,
                    "Roll": 0, "Pitch": 0, "Yaw" : 0,
                    "VerticalFOVUpper": -15,
                    "VerticalFOVLower": -25,
                    "HorizontalFOVStart": -20,
                    "HorizontalFOVEnd": 20,
                    "DrawDebugPoints": true,
                    "DataFrame": "SensorLocalFrame"
                }
            }
        }
    }
}

FPS will drop to below 10, and the RAM usage will keep increasing, by about a GB in some 10-15 seconds

As to how it worked earlier, maybe the Persistency parameter was not working?

https://forums.unrealengine.com/development-discussion/c-gameplay-programming/1539369-drawdebughelpers-h-outdated-persistent-lines-not-working

[nightduck]

Tested and working. I approve

[rajat2004]

@nightduck Great, thanks for testing!

[rajat2004]

Another change which can be done is to make DrawDebugPoints in the settings files such as ROS to False. However, not sure if this is actually something useful since they will generally be running the latest master for the ROS wrapper
Not very much in favour of this, if others think it's useful, then it can be changed

[nightduck]

I would vote to keep them visible. For aesthetics, if not functionality.