csv_overrides check_for_duplicates does nothing

[auscompgeek]

I can't see what type this is supposed to be... because I don't think any items are ever assigned to this 😕

I recall this bit was in one of the other functions previously. Think this ended up being broken after a recent refactor.

Originally posted by @auscompgeek in #1851 (comment)

[pokey]

oh wow nice catch 😅. looks like we are forgetting to update results_map in each iteration. We should fix and then do a manual check that it catches the bug. Ideally we could call the function with some mocks to add a real test that it catches duplicates