Removing 'No cluster_manager is associated with the provided pipeline!' logger error

Bug fix: removing the 'No cluster_manager is associated with the provided pipeline!' logger error message when a pipeline is present, but has no cluster manager. The bug in this scenario is that this case can be triggered when the user uses Interactive Beam in a way that automatically cleans up an individual pipeline (e.g. running InteractiveRunner() using a `with` clause).