[release/10.0.1xx-sr10] Restore native iOS 26 TabBar behavior (#37542)

Backport the isolated four-file Shell payload from #37542 without its unrelated inflight branch history.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: Copilot CI

src/Controls/tests/TestCases.Shared.Tests/Tests/Issues/XFIssue/Issue7396.cs

@@ -20,11 +20,6 @@ public Issue7396(TestDevice testDevice) : base(testDevice)
 	[Category(UITestCategories.Shell)]
 	public void BottomTabColorTest()
 	{
-		if (App is AppiumIOSApp iosApp && HelperExtensions.IsIOS26OrHigher(iosApp))
-		{
-			Assert.Ignore("Ignored due to a bug issue in iOS 26"); // Issue Link: https://github.com/dotnet/maui/issues/32125
-		}
-		//7396 Issue | Shell: Setting Shell.BackgroundColor overrides all colors of TabBar
 		App.WaitForElement(CreateBottomTabButton);
 		App.Tap(CreateBottomTabButton);
 		App.Tap(CreateBottomTabButton);

src/Controls/tests/TestCases.iOS.Tests/snapshots/ios-26/BottomTabColorTest.png

@@ -50,10 +50,6 @@ internal static void UpdateiOS15TabBarAppearance(
 			if (effectiveBarColor != null)
 			{
 				_tabBarAppearance.BackgroundColor = effectiveBarColor;
-				if (OperatingSystem.IsIOSVersionAtLeast(26))
-				{
-					tabBar.BackgroundColor = effectiveBarColor;
-				}
 			}
 
 			// Set BarTextColor