[iOS] CarouselView with CarouselViewHandler2 make app crash when Loop="False" and user scroll to the last position - fix (#26868)

* Update CarouselViewController2.cs

* Added a UI test for Matt

Author: kubaflo

src/Controls/src/Core/Handlers/Items2/iOS/CarouselViewController2.cs

@@ -49,7 +49,7 @@ public override UICollectionViewCell GetCell(UICollectionView collectionView, NS
 			return cell;
 		}
 
-		public override nint GetItemsCount(UICollectionView collectionView, nint section) => LoopItemsSource.LoopCount;
+		public override nint GetItemsCount(UICollectionView collectionView, nint section) => LoopItemsSource.Loop ? LoopItemsSource.LoopCount : LoopItemsSource.ItemCount;
 
 		void InitializeCarouselViewLoopManager()
 		{

src/Controls/tests/TestCases.HostApp/Issues/Issue26863.xaml

@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="utf-8" ?>
+<ContentPage xmlns="http://schemas.microsoft.com/dotnet/2021/maui"
+             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
+             x:Class="Maui.Controls.Sample.Issues.Issue26863"
+             x:Name="This">
+
+  <VerticalStackLayout BindingContext="{Binding Source={Reference This}}">
+    <Button AutomationId="button"
+            x:Name="button"
+            IsVisible="false"
+            Text="Click me"
+            Command="{Binding ScrollToCommand}"/>
+    <CarouselView
+      HeightRequest="200"
+      ItemsSource="{Binding List}"
+      HorizontalOptions="Fill"
+      x:Name="CV"
+      Loop="False">
+      <CarouselView.ItemTemplate>
+        <DataTemplate>
+          <Label HorizontalOptions="Fill"
+                 AutomationId="{Binding .}"
+                 Text="{Binding .}"/>
+        </DataTemplate>
+      </CarouselView.ItemTemplate>
+    </CarouselView>
+  </VerticalStackLayout>
+
+</ContentPage>

src/Controls/tests/TestCases.HostApp/Issues/Issue26863.xaml.cs

@@ -0,0 +1,25 @@
+using System.Collections.ObjectModel;
+
+namespace Maui.Controls.Sample.Issues
+{
+	[Issue(IssueTracker.Github, 26863, "CarouselView with CarouselViewHandler2 make app crash", PlatformAffected.iOS)]
+	public partial class Issue26863 : ContentPage
+	{
+		public Issue26863()
+		{
+			InitializeComponent();
+		}
+
+		public ObservableCollection<string> List { get; } = new();
+		public Command ScrollToCommand => new(() => CV.ScrollTo(2, 0, animate: true));
+
+		protected override void OnAppearing()
+		{
+			List.Clear();
+			List.Add("item1");
+			List.Add("item2");
+			List.Add("item3");
+			button.IsVisible = true;
+		}
+	}
+}

src/Controls/tests/TestCases.Shared.Tests/Tests/Issues/Issue26863.cs

@@ -0,0 +1,25 @@
+using NUnit.Framework;
+using UITest.Appium;
+using UITest.Core;
+
+namespace Microsoft.Maui.TestCases.Tests.Issues
+{
+	public class Issue26863 : _IssuesUITest
+	{
+		public Issue26863(TestDevice testDevice) : base(testDevice)
+		{
+		}
+
+		public override string Issue => "CarouselView with CarouselViewHandler2 make app crash";
+
+		[Test]
+		[Category(UITestCategories.CarouselView)]
+		public void AppShouldNotCrashOnScrollingCarouselViewWithoutLoop()
+		{
+			App.WaitForElement("button");
+			App.Click("button");
+
+			//The test passes if no crash is observed
+		}
+	}
+}