Test that stopOnFail works during github action

UnitTests/Application/ApplicationTests.cs

@@ -56,6 +56,7 @@ namespace Terminal.Gui.ApplicationTests {
 			Application.Shutdown ();
 		}
 
+		[Fact]
 		public void Fail ()
 		{
 			Assert.Fail("Test to prove stopOnFail is working. During CI/CD no more tests should run after this.");