Fix bug where artificial pipeline was erroneously run

The previous logic could accidentally set the boolean flag to `true`,
causing the pipeline to be run when it was not necessary.

Author: andyleejordan

src/PowerShellEditorServices/Services/PowerShell/Host/PsesInternalHost.cs

@@ -1261,7 +1261,12 @@ internal void OnPowerShellIdle(CancellationToken idleCancellationToken)
 
                     // If we're executing a PowerShell task, we don't need to run an extra pipeline
                     // later for events.
-                    runPipelineForEventProcessing = task is not ISynchronousPowerShellTask;
+                    if (task is ISynchronousPowerShellTask)
+                    {
+                        // We don't ever want to set this to true here, just skip if it had
+                        // previously been set true.
+                        runPipelineForEventProcessing = false;
+                    }
                     ExecuteTaskSynchronously(task, cancellationScope.CancellationToken);
                 }
             }