This commit adds support for using the vertex_ai/ prefix with models in the format:
vertex_ai/claude-3-7-sonnet@20250219
The implementation:
1. Adds explicit handling for the vertex_ai/ prefix in get_llm_provider()
2. Correctly sets the custom_llm_provider to 'vertex_ai'
3. Returns the base model name without the prefix
4. Includes tests to verify the functionality
This allows for proper provider detection and cost calculation with Vertex AI hosted models.
