Make sure glyphInfos usage is always in within bounds (#16120)

src/Avalonia.Base/Media/GlyphRun.cs

@@ -574,7 +574,10 @@ namespace Avalonia.Media
                     }
                 }
 
-                nextCluster = _glyphInfos[currentIndex].GlyphCluster;
+                if (_glyphInfos.Count > 0 && currentIndex <= _glyphInfos.Count)
+                {
+                    nextCluster = _glyphInfos[currentIndex].GlyphCluster;
+                }
             }
 
             var clusterLength = Math.Max(0, nextCluster - cluster);
@@ -639,7 +642,7 @@ namespace Avalonia.Media
         {
             int firstCluster, lastCluster;
 
-            if (Characters.IsEmpty)
+            if (Characters.IsEmpty || _glyphInfos.Count == 0)
             {
                 firstCluster = 0;
                 lastCluster = 0;

tests/Avalonia.Skia.UnitTests/Media/TextFormatting/TextLayoutTests.cs

@@ -1127,6 +1127,25 @@ namespace Avalonia.Skia.UnitTests.Media.TextFormatting
             }
         }
 
+        [Win32Fact("Font only available on Windows")]
+        public void Should_Handle_TextStyle_With_Ligature()
+        {
+            using (Start())
+            {
+                var text = "fi";
+
+                var typeface = new Typeface("Calibri");
+
+                var textLayout = new TextLayout(text, typeface, 12, Brushes.Black,
+                    textStyleOverrides: new[]
+                    {
+                        new ValueSpan<TextRunProperties>(1, 1,
+                            new GenericTextRunProperties(typeface, foregroundBrush: Brushes.White))
+                    });
+
+                Assert.NotNull(textLayout);
+            }
+        }
 
         private static IDisposable Start()
         {