fix(issues): Preserve suspect commit score ordering (#123043)

Suspect commit candidates could be reordered by user ID before selecting
preferred owners instead of keeping their score ranking. This was
introduced by the typing cleanup in
https://github.com/getsentry/sentry/pull/69211.

Preserves score order and adds regression coverage with more than two
eligible candidates.

Co-authored-by: Codex <noreply@openai.com>