loosen timestamp comparison (Azure#49016)

Author: trrwilson

sdk/openai/Azure.AI.OpenAI/tests/ResponsesTests.cs

@@ -257,7 +257,7 @@ public async Task ResponsesHelloWorldWithTool(string deploymentName)
             options);
 
         Assert.That(response.Id, Is.Not.Null.And.Not.Empty);
-        Assert.That(response.CreatedAt, Is.GreaterThan(DateTimeOffset.Now - TimeSpan.FromDays(1)));
+        Assert.That(response.CreatedAt, Is.GreaterThan(new DateTimeOffset(2025, 1, 1, 0, 0, 0, TimeSpan.Zero)));
         // Assert.That(response.Status, Is.EqualTo(ResponsesStatus.Completed));
         Assert.That(response.Model, Is.Not.Null.And.Not.Empty);
         Assert.That(response.PreviousResponseId, Is.Null);