[Testing] Fix for flaky test(VerifyEditorFocusedEvent) in CI (dotnet#31895)

This pull request updates the `VerifyEditorFocusedEvent` test method to
be asynchronous, improving reliability by adding a short delay after
tapping the editor. This ensures the focus event is properly triggered
before the assertion is made.

**Test reliability improvement:**
* Changed `VerifyEditorFocusedEvent` in `EditorFeatureTests.cs` to be an
`async Task`, and added a `Task.Delay(100)` after tapping the editor to
ensure the focus event has time to trigger before the test assertion.

Author: HarishKumarSF4517

src/Controls/tests/TestCases.Shared.Tests/Tests/FeatureMatrix/EditorFeatureTests.cs

@@ -72,7 +72,12 @@ public async Task VerifyEditorFocusedEvent()
 		App.WaitForElement("TestEditor");
 		App.Tap("TestEditor");
 		await Task.Delay(100);
-		App.DismissKeyboard();
+#if ANDROID || IOS
+		if (App.IsKeyboardShown())
+		{
+			App.DismissKeyboard();
+		}
+#endif
 		Assert.That(App.WaitForElement("FocusedLabel").GetText(), Is.EqualTo("Focused: Event Triggered"));
 	}