feat(components): add modelKwargs parameter to OpenAI & Custom OpenAI nodes

[v1nayG]

Description

This PR adds support for custom request parameters (modelKwargs) to both the standard OpenAI and OpenAI Custom Model chat nodes.

Why is this needed?

Users employing OpenAI-compatible local/custom backends (such as vLLM, LM Studio, Ollama, etc.) often need to pass custom body parameters (like repetition_penalty, guided_json, parallel_tool_calls, or logit_bias) that are not standard, first-class fields on the Flowise model card.

Adding the Model Kwargs JSON input under "Additional Parameters" provides a clean, flexible way to supply these custom configurations directly to the model's constructor without cluttering the main node UI.

Verification

• Built the packages successfully.
• Code style has been verified and formatted by the built-in pre-commit pretty-quick and eslint scripts.

[gemini-code-assist]

Code Review

This pull request introduces a new modelKwargs input parameter of type JSON to both the ChatOpenAI and ChatOpenAICustom chat model nodes, allowing users to pass additional parameters to the model body. The input is parsed and assigned to the model configuration, with error handling in place for invalid JSON. A review comment points out a copy-paste error in the error message of the ChatOpenAICustom node, which incorrectly references ChatOpenAI instead of ChatOpenAICustom.

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[gemini-code-assist]

There is a copy-paste error in the error message. It refers to ChatOpenAI instead of ChatOpenAICustom. Updating this will make debugging easier and keep the error messages accurate for this node.

Suggested change

	throw new Error("Invalid JSON in the ChatOpenAI's Model Kwargs: " + exception)
	throw new Error("Invalid JSON in the ChatOpenAICustom's Model Kwargs: " + exception)