Implement MaxLines property in WinUI LabelHandler

src/Compatibility/Core/src/Windows/LabelRenderer.cs

@@ -393,6 +393,7 @@ namespace Microsoft.Maui.Controls.Compatibility.Platform.UWP
 			}
 		}
 
+		[PortHandler]
 		void UpdateMaxLines(TextBlock textBlock)
 		{
 			if (Element.MaxLines >= 0)

src/Core/src/Handlers/Label/LabelHandler.Windows.cs

@@ -1,5 +1,3 @@
-using System;
-using Microsoft.Extensions.DependencyInjection;
 using Microsoft.UI.Xaml;
 using Microsoft.UI.Xaml.Controls;
 
@@ -40,8 +38,8 @@ namespace Microsoft.Maui.Handlers
 		[MissingMapper]
 		public static void MapTextDecorations(LabelHandler handler, ILabel label) { }
 
-		[MissingMapper]
-		public static void MapMaxLines(LabelHandler handler, ILabel label) { }
+		public static void MapMaxLines(LabelHandler handler, ILabel label) =>
+			handler.TextBlock?.UpdateMaxLines(label);
 
 		public static void MapPadding(LabelHandler handler, ILabel label) =>
 			handler.TextBlock?.UpdatePadding(label);

src/Core/src/Platform/Windows/TextBlockExtensions.cs

@@ -23,5 +23,17 @@ namespace Microsoft.Maui
 
 		public static void UpdatePadding(this TextBlock nativeControl, ILabel label) =>
 			nativeControl.UpdateProperty(TextBlock.PaddingProperty, label.Padding.ToNative());
+
+		public static void UpdateMaxLines(this TextBlock nativeControl, ILabel label)
+		{
+			if (label.MaxLines >= 0)
+			{
+				nativeControl.MaxLines = label.MaxLines;
+			}
+			else
+			{
+				nativeControl.MaxLines = 0;
+			}
+		}
 	}
 }