Fixes the following error that cause client crashes usually when you log in while being mounted on an elk. This harmony patch just ignores the exception. 

System.ArgumentException: Position is not a number at Vintagestory.Client.NoObf.NetworkAPI.SendPlayerPositionPacket() in VintagestoryLib\Client\API\NetworkAPI.cs:line 240 at Vintagestory.GameContent.EntityBehaviorPlayerPhysics.OnRenderFrame(Single dt, EnumRenderStage stage) in VSEssentials\Entity\Behavior\BehaviorPlayerPhysics.cs:line 395 at Vintagestory.Client.NoObf.ClientEventManager.TriggerRenderStage(EnumRenderStage stage, Single dt) in VintagestoryLib\Client\Util\ClientEventManager.cs:line 188 at Vintagestory.Client.NoObf.ClientMain.MainRenderLoop(Single dt) in VintagestoryLib\Client\ClientMain.cs:line 825 at Vintagestory.Client.GuiScreenRunningGame.RenderToPrimary(Single dt) in VintagestoryLib\Client\MainMenu\Screens\GuiScreenRunningGame.cs:line 161 at Vintagestory.Client.ScreenManager.Render(Single dt) in VintagestoryLib\Client\ScreenManager.cs:line 695 at Vintagestory.Client.ScreenManager.OnNewFrame(Single dt) in VintagestoryLib\Client\ScreenManager.cs:line 670 at Vintagestory.Client.NoObf.ClientPlatformWindows.window_RenderFrame(FrameEventArgs e) in VintagestoryLib\Client\ClientPlatform\GameWindow.cs:line 88 at OpenTK.Windowing.Desktop.GameWindow.Run()

Only relevant for VS 1.20.12 and most likely fixed in 1.21