Propage exceptions thrown during the embedded web server initialization

src/OpenIddict.Client.SystemIntegration/OpenIddictClientSystemIntegrationHttpListener.cs

@@ -92,15 +92,15 @@ public sealed class OpenIddictClientSystemIntegrationHttpListener : BackgroundSe
         }
 
         // Ignore exceptions indicating that the host is shutting down and return immediately.
-        catch (OperationCanceledException) when (stoppingToken.IsCancellationRequested)
+        catch (OperationCanceledException exception) when (stoppingToken.IsCancellationRequested)
         {
-            _source.SetResult(result: null);
+            _source.TrySetException(exception);
             return;
         }
 
         catch (Exception exception) when (!OpenIddictHelpers.IsFatal(exception))
         {
-            _source.SetResult(result: null);
+            _source.TrySetException(exception);
             throw;
         }