Add Vertex AI models

[AlanBacker]

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1. Is this request related to a challenge you're experiencing? Tell me about your story.

The list of Vertex AI models in Dify doesn't match the models in the Vertex AI panel; missing models need to be added. Thanks

2. Additional context or comments

I'd like to ask, if I enable Function calls when calling Vertex AI, will it cause the error "[vertex_ai] Error: module 'vertexai.generative_models' has no attribute 'Schema'", is this my fault, a project defect, or does Vertex AI simply not support function calls? I would be very grateful if you could answer my question!

3. Can you help us with this feature?

• I am interested in contributing to this feature.