fix(config) config schema newline (#10323)

## Summary
Looks like we may have introduced a formatting issue in recent PRs.

## Testing
- [x] ran `just write-config-schema`

codex-rs/core/config.schema.json

@@ -1569,4 +1569,4 @@
   },
   "title": "ConfigToml",
   "type": "object"
-}
+}