Mixtral-8x7B-Instruct-v0.1 is no longer on Together AI's serverless tier
and now requires a dedicated endpoint, causing multiple tests to fail in CI:
- test_together_ai.py::TestTogetherAI::test_empty_tools
- test_completion.py::test_completion_together_ai_stream
- test_completion.py::test_customprompt_together_ai
- test_completion.py::test_completion_custom_provider_model_name
- test_text_completion.py::test_async_text_completion_together_ai
Qwen/Qwen3.5-9B is currently serverless on Together AI and supports
function calling, satisfying BaseLLMChatTest capability requirements.