Pinning lower litellm version for OpenAI reasoning effort support

[jamesbraza]

Ensuring reasoning effort is passed as expected, with tests.

With litellm<1.75.6 and GPT-5 reasoning effort, you will get blown up:

E               litellm.exceptions.UnsupportedParamsError: litellm.UnsupportedParamsError: openai does not support parameters: ['reasoning_effort'], for model=gpt-5-2025-08-07. To drop these, set `litellm.drop_params=True` or for proxy:
E               
E               `litellm_settings:
E                drop_params: true`
E               . 
E                If you want to use these params dynamically send allowed_openai_params=['reasoning_effort'] in your request.. Received Model Group=gpt-5-2025-08-07
E               Available Model Group Fallbacks=None LiteLLM Retried: 2 times, LiteLLM Max Retries: 3

[Copilot]

Pull Request Overview

This PR updates the minimum version of litellm from 1.63.5 to 1.75.6 to ensure proper OpenAI reasoning effort support. The test suite has been refactored to validate reasoning effort functionality across both OpenAI (GPT-5) and Anthropic (Claude 3.7 Sonnet) models with different effort levels.

• Refactored test from a single Anthropic-specific test to a parameterized test covering multiple models and effort levels
• Added validation for reasoning effort by checking response length ranges and verifying provider-specific reasoning content
• Added VCR cassettes capturing API responses for parameterized test scenarios

Reviewed Changes

Copilot reviewed 7 out of 8 changed files in this pull request and generated no comments.

File	Description
packages/lmi/tests/test_llms.py	Refactored test_anthropic_model to test_reasoning_effort with parameterized model and effort level testing
packages/lmi/pyproject.toml	Updated minimum litellm version from 1.63.5 to 1.75.6 for reasoning effort support
packages/lmi/tests/cassettes/*.yaml	Added VCR cassettes for parameterized test scenarios, deleted old cassette

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[sidnarayanan]

Nice