[inspect] Only show those datafied items in collection that have unique datafy represantation

[alexander-yakushev]

This slightly changes how we handle the display of datafied collections. If a collection has items in it where datafy returns something meaningful, we now will only show those meaningful datafies, without the repeats of regular values.

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• You've added tests to cover your change(s)
• You've updated the changelog (if adding/changing user-visible functionality)