DatasetConsumptionConfig and PipelineParameter cannot be reused

Following the tutorial to create ML datasets as pipeline parameters:
https://github.com/Azure/MachineLearningNotebooks/blob/master/how-to-use-azureml/machine-learning-pipelines/intro-to-pipelines/aml-pipelines-showcasing-dataset-and-pipelineparameter.ipynb

This requires the creation of PipelineParameter and then DatasetConsumptionConfig objects.
If you have multiple steps which require the same dataset input, you would expect to be able to use the same PipelineParameter for all the steps. However when that PipelineParameter is used with a DatasetConsumptionConfig this doesn't work.

When building the pipeline we get the error:
`'PipelineDataset' object has no attribute '_get_datapath'`

Seems the object is altered when it is used, so when we use it a second time it breaks.

The work around at the moment is to create a new PipelineParameter for every step that uses the dataset, hence the number of pipeline parameters to configure grows very fast.

Tail end of error log (can't copy/paste text)

Inizia con il tutorial collegato aml-pipelines-showcasing-dataset-and-pipelineparameter.ipynb e riproduci la pipeline usando un PipelineParameter con più oggetti DatasetConsumptionConfig. Traccia la costruzione della pipeline in relazione all’errore segnalato «_get_datapath». Il lavoro è completato quando lo stesso input del dataset può essere riutilizzato tra gli step e la pipeline viene compilata correttamente.

Scritto dal modello di indicizzazione a partire dal testo della issue.