[WV-4665] Fix Election Finder search joining candidates via contest_office_list.

[Almee98]

What github.com/wevote/WebApp/issues does this fix? WV-4665

Changes included this pull request?

• Election Finder list search now joins name matches using each candidate’s contest_office_list (with a fallback to the leftover google_civic_election_id) so a person is attached to every linked election that appears in electionsRetrieve.
• This is the Upcoming “Warren” miss: candidates whose flat election id was blank or stale were dropped even when they had an upcoming link.
• Still in progress on this ticket: duplicate candidate rows in search results (e.g. many identical “Andrea K. Bailey” / “Kellie Warren” lines). I’m debugging that next and it is not part of this change.