Moves InlineUIContainer Child measure and arrange to the IInlineHost (#8849)

src/Avalonia.Controls/Documents/InlineUIContainer.cs

@@ -87,18 +87,7 @@ namespace Avalonia.Controls.Documents
 
             public override TextRunProperties? Properties { get; }
 
-            public override Size Size
-            {
-                get
-                {
-                    if (!Control.IsMeasureValid)
-                    {
-                        Control.Measure(Size.Infinity);
-                    }
-
-                    return Control.DesiredSize;
-                }
-            }
+            public override Size Size => Control.DesiredSize;
 
             public override double Baseline
             {
@@ -118,7 +107,7 @@ namespace Avalonia.Controls.Documents
 
             public override void Draw(DrawingContext drawingContext, Point origin)
             {             
-                Control.Arrange(new Rect(origin, Size));                
+                //noop            
             }
         }
     }

src/Avalonia.Controls/RichTextBlock.cs

@@ -544,6 +544,32 @@ namespace Avalonia.Controls
             }
         }
 
+        protected override Size MeasureOverride(Size availableSize)
+        {
+            foreach (var child in VisualChildren)
+            {
+                if (child is Control control)
+                {
+                    control.Measure(Size.Infinity);
+                }
+            }
+            
+            return base.MeasureOverride(availableSize);
+        }
+
+        protected override Size ArrangeOverride(Size finalSize)
+        {
+            foreach (var child in VisualChildren)
+            {
+                if (child is Control control)
+                {
+                    control.Arrange(new Rect(control.DesiredSize));
+                }
+            }
+            
+            return base.ArrangeOverride(finalSize);
+        }
+
         private string GetSelection()
         {
             if (!IsTextSelectionEnabled)