fix: Dedup search, add schema to hybrid func, fix delete error

[neilyio]

What

Fixing a few small issues with rank_hybrid, as well as handling a unusual deletion case we're seeing in CI.

• rank_hybrid was not previously working with schemas not on the search_path.
• rank_hybrid was returning stale rows when used outside of Postgres index scan, because we couldn't rely on Postgres filtering.
• Deleting Tantivy files occasionally fails, because we try to delete a file that doesn't exist. We now just check for a NotFound error, and ignore it if we see it.

Tests

New test to confirm rank_hybrid results.