cubicweb-container #3832732 `config.border_relations()` may return duplicated result [resolved]

I don't have a test case (yet) for this. A possible fix would be to use a set.

prioritynormal
typebug
done in2.5.0
load1.000
load left0.000
closed by#f6e35ac6586d Don't return duplicate relations in `border_relations` method
patchDon't return duplicate relations in `border_relations` method [applied]