Fix unclosed aiohttp connector warnings in Gemini pipeline

- Add finally block in pipe() method to properly close genai.Client
- Check for aclose() and close() methods on the client
- Add try-finally in get_google_models() with note about sync limitations
- Log debug messages when client is closed successfully
- This prevents "Unclosed connector" warnings from aiohttp

Co-authored-by: owndev <69784886+owndev@users.noreply.github.com>

Author: Copilot