do not dedupe disparate unit numbers at same address

[missinglink]

as mentioned in https://github.com/pelias/openaddresses/pull/504 the current deduplication behaviour considers all units at the same address to be duplicate, therefore 'squashing them' into a single response.

this PR modifies this behaviour so that each individual unit number at an address returns a row in the results.

I'm opening this as DRAFT for now since @orangejulius mentioned in https://github.com/pelias/openaddresses/pull/504#issuecomment-1054461416 that we might consider alternatives, I wanted to have a PR open to remind us.

[missinglink]

duplicate of https://github.com/pelias/api/pull/1472