feat: support json schema for gemini models

[hjlarry]

Summary

Tip

Close issue syntax: Fixes #<issue number> or Resolves #<issue number>, see documentation for more details.

Change List

1. add json_schema for gemini models, offical doc
2. remove the response_format, which is conflict with json_schema
3. use max_output_tokens instead of max_tokens_to_sample
4. remove GEMINI_BLOCK_MODE_PROMPT and logger, seems not used in any place
5. deprecated gemini-1.0-pro and gemini-1.0-pro-vision

Screenshots

test schema:

{  
        "type": "object",  
        "properties": {  
            "location": {  
                "type": "string",  
                "description": "The location to get the weather for"  
            },  
            "unit": {  
                "type": "string",  
                "description": "The unit to return the temperature in",  
                "enum": ["F", "C"]  
            }  
        },  
        "required": ["location", "unit"]  
}

Checklist

Important

Please review the checklist below before submitting your pull request.

• This change requires a documentation update, included: Dify Document
• I understand that this PR may be closed in case there was no previous discussion or issues. (This doesn't apply to typos!)
• I've added a test for each change that was introduced, and I tried as much as possible to make a single atomic change.
• I've updated the documentation accordingly.
• I ran dev/reformat(backend) and cd web && npx lint-staged(frontend) to appease the lint gods

[wonderlabsio]

Could you help check if possible to support gemini backed by Google Cloud Vertex? currently seems the json schema only enabled for google AI studio models

[hjlarry]

Could you help check if possible to support gemini backed by Google Cloud Vertex? currently seems the json schema only enabled for google AI studio models

the google publish a new API yesterday, which support both Vertex AI and Google AI : https://googleapis.github.io/python-genai/index.html
maybe we can working on this later to support the feature.