Fix structured output leaks in tool-calling loops (#5897)

* Fix structured output leaks in tool-calling loops

* addressing comments

* drop scripts

* Update Gemini agent tests to include structured output with thoughts and bump model version to 2.5-flash

* merge

* Update Anthropic test cases to use new model and tool structure

- Changed the model from "claude-3-5-haiku-20241022" to "claude-sonnet-4-6" in the test setup.
- Updated the request and response formats in the YAML test cassette to reflect the new tool structure and improved content formatting.
- Adjusted the expected response body to match the new output format from the assistant, including changes in tool usage and response details.
- Increased rate limit values in the response headers for better testing scenarios.

* adjusted bedrock cassettes

* adjusting cassettes for bedrock

* fix test

* Update VCR configuration to use 'host' instead of 'bedrock_host' for request matching