fix(ab-transport): final review I2 — wire DeviceSessionPool.Shared to the host logger

ConfigureSharedLogger had no production caller, so the pool's only
diagnostics (first-wins options conflicts, scheduler/close failures)
went to NullLogger. DriverFactoryBootstrap now configures it from the
driver registry factory and from the AbCip/AbLegacy probe factories
(admin-only nodes reach the pool only through Test Connect). Wiring tests
reset the pool to a null logger first, so removing the call goes red
(verified).

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

tests/Server/ZB.MOM.WW.OtOpcUa.Host.Tests/Configuration/AbCipDriverDefaultsOptionsTests.cs

@@ -20,6 +20,7 @@ namespace ZB.MOM.WW.OtOpcUa.Host.Tests.Configuration;
 ///     node (Libplctag) against the compiled default (Native), so a wiring that ignores the node value goes red.
 /// </summary>
 [Trait("Category", "Unit")]
+[Collection(AbTransportSharedPoolCollection.Name)] // resolves the registry, which configures the shared pool
 public sealed class AbCipDriverDefaultsOptionsTests
 {
     private const string NoKey = """{"devices":[{"hostAddress":"ab://10.0.0.1/1,0"}],"probe":{"enabled":false}}""";