endtoend: regenerate the process-plugin golden for PostgreSQL 16

The case shares codegen_json's schema, so the pg_attribute layout
change from regenerating the dialect against PostgreSQL 16 reaches its
golden too. It was skipped locally for want of a sqlc-gen-json binary
on PATH, which is why the first regeneration missed it.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Y2wUuK6WfHSyT8XWMJFAuy

Author: claude