perf(tests): isolate network E2E and await QUIC cleanup

backend/tests/MoShiro.Backend.Tests/ProbeHarness.cs

@@ -38,7 +38,7 @@ public sealed class ProbeHarness : IAsyncDisposable
 
         ProbeFile file = Fleet.Hosting.NodeConfig.Load(path, ProbeConfigContext.Default.ProbeFile);
         configure?.Invoke(file);
-        var app = new ProbeApp(file, enrolled.Identity, directory, TimeProvider.System, new Fleet.Hosting.ConsoleNodeLog(TimeProvider.System, Console.Out));
+        var app = new ProbeApp(file, enrolled.Identity, directory, TimeProvider.System, NullNodeLog.Instance);
         return new ProbeHarness(directory, app, enrolled) { ProbeId = enrolled.ProbeId };
     }