Fixes leading space GlyphRun.InkBounds (#13268)

* Make sure glyph bounds of whitespaces are calculated properly

* Add unit test

src/Skia/Avalonia.Skia/GlyphRunImpl.cs

@@ -70,6 +70,11 @@ namespace Avalonia.Skia
                 var gBounds = glyphBounds[i];
                 var advance = glyphInfos[i].GlyphAdvance;
 
+                if(gBounds.Width == 0)
+                {
+                    gBounds = new SKRect(0, 0, (float)advance, 1);
+                }
+
                 runBounds = runBounds.Union(new Rect(currentX + gBounds.Left, baselineOrigin.Y + gBounds.Top, gBounds.Width, gBounds.Height));
 
                 currentX += advance;

tests/Avalonia.Skia.UnitTests/Media/GlyphRunTests.cs

@@ -175,6 +175,22 @@ namespace Avalonia.Skia.UnitTests.Media
             }
         }
 
+        [Fact]
+        public void GlyphRun_With_Leading_Space_Has_Correct_InBounds()
+        {
+            using (Start())
+            {
+                var typeface = new Typeface("resm:Avalonia.Skia.UnitTests.Assets?assembly=Avalonia.Skia.UnitTests#Inter");
+                var options = new TextShaperOptions(typeface.GlyphTypeface, 14);
+                var shapedBuffer = TextShaper.Current.ShapeText(" ", options);
+
+                var glyphRun1 = CreateGlyphRun(shapedBuffer);
+                var bounds = glyphRun1.InkBounds;
+
+                Assert.Equal(shapedBuffer[0].GlyphAdvance, bounds.Width);
+            }
+        }
+
         private static List<Rect> BuildRects(GlyphRun glyphRun)
         {
             var height = glyphRun.Bounds.Height;