openaiclient: Fix updateToolCalls method for calls proxied with LiteLLM

[dzbanek717]

When using LiteLLM as LLM proxy for accessing multiple models with one LLM agent in streaming mode the parameter type: function is always provided due to API conversion on LiteLLM side.

Despite the fact that it seems to be a problem on integration with LiteLLM side the whole problem lays in updateToolCalls function check. The assumption that type is not provided seems to be based more on the observation, rather than actual contract.

Basing on function name not being provided and part of arguments being provided this assumption seems to be also fine. Providing arguments for next tool shall always start with tool name. Therefore we are receiving parts of arguments until we received a new name. And it makes OpenAI Client compatible with both standard OpenAI API and LiteLLM proxy.

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[dzbanek717]

Hello @tmc , any chance on reviewing this?