backend: require confirmation for signed channel updates [CI]

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

@@ -54,8 +54,9 @@ public sealed class ProbeEndToEndTests
         // 吊销：面板立刻断开它，之后连不上
         using HttpResponseMessage revoked = await _backend.Admin.PostAsync(path + "/revoke", null);
         revoked.EnsureSuccessStatusCode();
-        await BackendFixture.EventuallyAsync(async () => !(await _backend.GetJsonAsync(_backend.Admin, path))["online"]!.GetValue<bool>(), because: "a revoked probe is disconnected and cannot come back");
-        Assert.False(probe.App.Link.IsConnected);
+        await BackendFixture.EventuallyAsync(async () =>
+            !(await _backend.GetJsonAsync(_backend.Admin, path))["online"]!.GetValue<bool>() && !probe.App.Link.IsConnected,
+            because: "a revoked probe is disconnected and cannot come back");
     }
 
     [Fact]