Add "uniqueItems: true" to certain array fields in matrix.json

[JoshuaFortriede]

For which schema is a change/update being suggested?

Matrix.json (module/protocol/matrix.json)

What should the change/update be?

For the fields "data_normalization_methods" and "derivation_process", add the jsonschema field "uniqueItems" and set it to a value of true.

This update constitutes a major change to the schema(s) it affects.

What new field(s) need to be changed/added?

None

Why is the change requested?

This change provides 2 uses. First, it ensures that the values in these arrays have no duplicates; these arrays should be unique and there should be no reason for the same value being present twice. Second, as groups create implementation layers, a "uniqueItems" value of "true" produces different UI elements (checkboxes instead of dropdown arrays).

While I understand implementation should be kept separate, I do believe there is a data standards reason for this change, and that change will also assist more usable UI implementations.

Other Considerations
It is quite possible that this jsonschema field (uniqueItems) should be used elsewhere in the HCA metadata schema.