ColorGradient - fixed edgecase in GetColor

src/Artemis.Core/Models/Profile/Colors/ColorGradient.cs

@@ -246,6 +246,10 @@ public class ColorGradient : IList<ColorGradientStop>, IList, INotifyCollectionC
         if (stop2Index == 0)
             return _stops[0].Color;
         
+        //if the position is after the last stop, return that color
+        if (stop2Index == -1)
+            return _stops[^1].Color;
+
         //interpolate between that one and the one before
         int stop1Index = stop2Index - 1;