We were failing until now, but since the uid is sure to be unique,
we can just assume that if it's the same uid it's the same content.
This means we can just gracefully fail as the data is the same.
Until now, we were raising an error, but we now just do nothing
and consider it a success.
This is especially useful when a network error caused an item to
be uploaded but not updated on the client side.
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