add automation peer for UserControl (#17480)

* add automation peer for UserControl

* fix automation name

* change base class to ControlAutomationPeer

Author: baochenw

src/Avalonia.Controls/Automation/Peers/UserControlAutomationPeer.cs

@@ -0,0 +1,14 @@
+using Avalonia.Automation;
+using Avalonia.Automation.Peers;
+
+namespace Avalonia.Controls.Automation.Peers;
+
+public class UserControlAutomationPeer : ControlAutomationPeer
+{
+    public UserControlAutomationPeer(UserControl owner)
+        : base(owner)
+    {
+    }
+    
+    protected override AutomationControlType GetAutomationControlTypeCore() => AutomationControlType.Custom;
+}

src/Avalonia.Controls/UserControl.cs

@@ -1,3 +1,5 @@
+using Avalonia.Automation.Peers;
+using Avalonia.Controls.Automation.Peers;
 using Avalonia.Styling;
 
 namespace Avalonia.Controls
@@ -7,6 +9,6 @@ namespace Avalonia.Controls
     /// </summary>
     public class UserControl : ContentControl
     {
-
+        protected override AutomationPeer OnCreateAutomationPeer() => new UserControlAutomationPeer(this);
     }
 }