@google/vertexai is deprecated. So, we should support @google/genai instead.

[!NOTE] The VertexAI class and all its dependencies in the Vertex AI SDK are deprecated as of June 24, 2025 and will be removed on June 24, 2026. Please use the Google Gen AI SDK to access Gemini features. See the migration guide for details.

https://github.com/googleapis/nodejs-vertexai