Added the test case

Author: NanthiniMahalingam

src/Controls/tests/TestCases.HostApp/Issues/Issue29633.cs

@@ -0,0 +1,29 @@
+namespace Maui.Controls.Sample.Issues;
+
+[Issue(IssueTracker.Github, 29633, "[Android] Picker Does Not Show Selected Item Highlight", PlatformAffected.Android)]
+public class Issue29633 : ContentPage
+{
+	public Issue29633()
+	{
+		var items = new List<string>
+		{
+			"Apple", "Banana", "Cherry", "Date", "Elderberry",
+			"Fig", "Grape", "Honeydew", "Kiwi", "Lemon"
+		};
+
+		var picker = new Picker()
+		{
+			AutomationId = "HighlightPickerItem",
+			ItemsSource = items,
+			SelectedItem = items[6]
+		};
+
+		Content = new StackLayout
+		{
+			Children =
+			{
+				picker
+			}
+		};
+	}
+}

src/Controls/tests/TestCases.Shared.Tests/Tests/Issues/Issue29633.cs

@@ -0,0 +1,23 @@
+using NUnit.Framework;
+using UITest.Appium;
+using UITest.Core;
+
+namespace Microsoft.Maui.TestCases.Tests.Issues;
+
+public class Issue29633 : _IssuesUITest
+{
+	public Issue29633(TestDevice testDevice) : base(testDevice)
+	{
+	}
+
+	public override string Issue => "[Android] Picker Does Not Show Selected Item Highlight";
+
+	[Test]
+	[Category(UITestCategories.Picker)]
+	public void PickerShouldShowSelectedItemHighlight()
+	{
+		App.WaitForElement("HighlightPickerItem");
+		App.Click("HighlightPickerItem");
+		VerifyScreenshot();
+	}
+}