Added UI Test

Author: kubaflo

src/Controls/tests/TestCases.HostApp/Issues/Issue29798.cs

@@ -0,0 +1,49 @@
+namespace Maui.Controls.Sample.Issues;
+
+[Issue(IssueTracker.Github, 29798, "Tab becomes blank after specific navigation pattern", PlatformAffected.iOS)]
+public class Issue29798 : Shell
+{
+	public Issue29798()
+	{
+		Routing.RegisterRoute(nameof(Issue29798Page), typeof(Issue29798Page));
+
+		Items.Add(new ShellContent()
+		{
+			Title = "Tab1",
+			Content = new ContentPage()
+			{
+				Title = "Test",
+				Content = new Button
+				{
+					Text = "Go to Page 2",
+					AutomationId = "GotoPage2",
+					Command = new Command(async () => await Current.GoToAsync(nameof(Issue29798Page)))
+				}
+			}
+		});
+
+		Items[0].Items.Add(new ShellContent()
+		{
+			Content = new ContentPage()
+		});
+	}
+}
+
+public class Issue29798Page : ContentPage
+{
+	public Issue29798Page()
+	{
+		Title = "Page 2";
+		Content = new StackLayout
+		{
+			Children =
+				{
+					new Label
+					{
+						AutomationId = "Page2Label",
+						 Text = "Welcome to Page 2"
+					}
+				}
+		};
+	}
+}

src/Controls/tests/TestCases.Shared.Tests/Tests/Issues/Issue29798.cs

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+#if IOS
+using NUnit.Framework;
+using UITest.Appium;
+using UITest.Core;
+
+namespace Microsoft.Maui.TestCases.Tests.Issues;
+
+public class Issue29798 : _IssuesUITest
+{
+	public Issue29798(TestDevice testDevice) : base(testDevice)
+	{
+	}
+
+	public override string Issue => "Tab becomes blank after specific navigation pattern";
+
+	[Test]
+	[Category(UITestCategories.Shell)]
+	public void TabShouldNotBeBlackAfterTabNavigation()
+	{
+		App.WaitForElement("GotoPage2");
+		App.Tap("GotoPage2");
+		App.WaitForElement("Page2Label");
+		App.Tap("Tab1");
+		App.WaitForElement("GotoPage2");
+		App.Tap("GotoPage2");
+		App.WaitForElement("Page2Label");
+		App.Tap("Tab1");
+		App.WaitForElement("GotoPage2");
+	}
+}
+#endif