Fix onepoint display

[powerpdw]

I've fixed diaplay bug on one-point display.

[Before]

###[After]

[beto-rodriguez]

Thanks again for this PR.

I am not able to reproduce this case.

I see the current version works properly when there is only one point in a line series, am I missing something?

[powerpdw]

I tested [Scatter]-[Basic] sample.
In ViewModel.cs, The code I tested is as follows.
If you test the code below you will find the problem.

using LiveChartsCore;
using LiveChartsCore.Defaults;
using LiveChartsCore.SkiaSharpView;
using System.Collections.Generic;
using System.Collections.ObjectModel;

namespace ViewModelsSamples.Scatter.Basic
{
    public class ViewModel
    {
        public IEnumerable<ISeries> Series { get; set; } = new ObservableCollection<ISeries>
        {
            new ScatterSeries<ObservablePoint>
            {
                Values = new ObservableCollection<ObservablePoint>
                {
                    new ObservablePoint(20, 20)                    
                }
            }
        };
    }
}