fix: sync rows query after error

[foredstudio]

Fixes #3707.

When a query uses the rows option, _getRows sends Flush instead of pipelining Sync. If PostgreSQL returns an ErrorResponse, it ignores subsequent messages until a Sync arrives, so the client can remain permanently stuck waiting for ReadyForQuery.

This sends Sync from handleError only for rows-mode queries, matching the existing rows-mode handling in handleCommandComplete and handleEmptyQuery. Normal queries keep their existing behavior.

Tests added for both rows-mode and normal-query error paths.

Validation:

• node test/unit/client/query-error-sync-tests.js
• make test-unit
• eslint packages/pg/lib/query.js packages/pg/test/unit/client/query-error-sync-tests.js