[Testing] Fix for flaky UITests in CI that occasionally fail - 8 (#28828)

* improve stability to flaky test

* Update Issue7678.cs

Author: HarishKumarSF4517

src/Controls/tests/TestCases.Android.Tests/snapshots/android/HeaderFooterGridHorizontalWorks.png

@@ -17,10 +17,14 @@ public Bugzilla34912(TestDevice testDevice) : base(testDevice)
 	[Category(UITestCategories.ListView)]
 	public void Bugzilla34912Test()
 	{
+		App.WaitForElement("Allen");
 		App.Tap("Allen");
 		App.WaitForElement("You tapped Allen");
+		App.WaitForElement("OK");
 		App.Tap("OK");
+		App.WaitForElement("Disable ListView");
 		App.Tap("Disable ListView");
+		App.WaitForElement("Allen");
 		App.Tap("Allen");
 		App.WaitForNoElement("You tapped Allen");
 	}

src/Controls/tests/TestCases.Shared.Tests/Tests/Issues/Bugzilla/Bugzilla34912.cs

@@ -15,7 +15,7 @@ public Issue7678(TestDevice device) : base(device)
 		[Category(UITestCategories.CarouselView)]
 		public void VerifyCarouselViewItemsRenderAfterBinding()
 		{
-			App.WaitForElement("carouselView", timeout: TimeSpan.FromSeconds(2));
+			App.WaitForElement("carouselView", timeout: TimeSpan.FromSeconds(4));
 			App.WaitForElementTillPageNavigationSettled("1");
 		}
 	}