Support for grounding in gemini-2.0-flash-001 with langchain-google-vertexai

Hi,

It seems that langchain-google-vertexai does not currently support the grounding feature of gemini-2.0-flash-001. I couldn't find any relevant documentation or examples indicating its support.

Are there any plans to add this feature in the future? If so, is there an estimated timeline?

Thank you!

