chore: import upstream snapshot with attribution

dotnet/test/VectorData/VectorData.ConformanceTests/Xunit/ITestCondition.cs

@@ -0,0 +1,10 @@
+// Copyright (c) Microsoft. All rights reserved.
+
+namespace VectorData.ConformanceTests.Xunit;
+
+public interface ITestCondition
+{
+    ValueTask<bool> IsMetAsync();
+
+    string SkipReason { get; }
+}