edit_dataset_metadata replace bug

[arielg96]

Even though I set "replace" = True. I get:

You may not add data to a field that already has data and does not allow multiples. Use is_replace=true to replace existing data.

I even printed out the params with the result: {'replace': True}

[pdurbin]

Hmm, I wonder if this would be fixed by this PR:

• #146