Adds failing Test to check handling within GitHub Actions

Author: soernt

source/Marten.AspNetCore.Identity.Tests/FailingTest.cs

@@ -0,0 +1,12 @@
+using Xunit;
+
+namespace Marten.AspNetCore.Identity.Tests;
+
+public class FailingTest
+{
+    [Fact]
+    public void DoesFail()
+    {
+        Assert.True(false);
+    }
+}