raw_data_path for ewoks should take into account processed datasets

This issue is related to workflow/ewoksapps/ewoksmx#1

Currently, icat-plus send to ewoks a parameter called raw_data_path which contains the path to the location of the dataset:

input.raw_data_path = input.datasets ? input.datasets.map((d) => d.location) : [];

However, when the dataset that needs reprocessing is a processed dataset we should provide the localtion to the raw dataset (the input)