Added ability to configure concurrent_requests in litellm_model.py (#911)
* Added ability to configure concurrent_requests in litellm_model.py
* Update src/lighteval/models/endpoints/litellm_model.py
Co-authored-by: Nathan Habib <30601243+NathanHB@users.noreply.github.com>
* Updated docstring for new concurrent_requests parameter in LiteLLMModelConfig
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Co-authored-by: Nathan Habib <30601243+NathanHB@users.noreply.github.com>