Flag or remove redundant relations

[pgaudet]

When curators 'edited' a relation between two entities in noctua (rather than first deleting it), both relations were kept, although only the newest one was shown in the VPE (the GE correctly shown both)
See geneontology/noctua-visual-pathway-editor#170 and geneontology/noctua-visual-pathway-editor#179

We need to remove the redundant relation, somehow. The VPE seems to pick the correct one; could we use the same logic to aumtomatically update the annotations?

@balhoff @tmushayahama @vanaukenk

[pgaudet]

Noting that the fix is currently on dev, so we should not try to fix the data until this has been merged to prod.
See geneontology/noctua-visual-pathway-editor#196