test(runtime): de-flake Rediscovery_flag_persists (vacuous AwaitAssert, no publish trigger)

The AwaitAssert lambdas returned bool into an Action, so they never waited;
the test raced the rediscovery publish (5-22% failure on base too). Make the
asserts real and drive the republish with a short health poll interval.

Claude-Session: https://claude.ai/code/session_01Ef2ozxS7QPanGT8uoATbTe

tests/Server/ZB.MOM.WW.OtOpcUa.Runtime.Tests/Drivers/DriverInstanceActorRediscoverySignalTests.cs

@@ -95,19 +95,20 @@ public sealed class DriverInstanceActorRediscoverySignalTests : RuntimeActorTest
         var publisher = new RecordingHealthPublisher();
         var parent = CreateTestProbe();
         parent.IgnoreMessages(_ => true);
-        var actor = parent.ChildActorOf(DriverInstanceActor.Props(driver, healthPublisher: publisher));
+        var actor = parent.ChildActorOf(DriverInstanceActor.Props(driver, healthPublisher: publisher,
+            healthPollInterval: TimeSpan.FromMilliseconds(200)));
 
         actor.Tell(new DriverInstanceActor.InitializeRequested("{}"));
         AwaitAssert(() => publisher.Published.Count.ShouldBeGreaterThan(0), TimeSpan.FromSeconds(3));
         driver.RaiseRediscovery("agent-instance-changed");
         AwaitAssert(
-            () => publisher.Published.Any(p => p.RediscoveryNeededUtc is not null),
+            () => publisher.Published.Any(p => p.RediscoveryNeededUtc is not null).ShouldBeTrue(),
             TimeSpan.FromSeconds(3));
 
         // Force a further publish by changing something else about the driver's health.
         driver.SetLastError("transient read failure");
         AwaitAssert(
-            () => publisher.Published.Any(p => p.LastError == "transient read failure"),
+            () => publisher.Published.Any(p => p.LastError == "transient read failure").ShouldBeTrue(),
             TimeSpan.FromSeconds(3));
 
         var latest = publisher.Published[^1];