Add remove_from_body to OpenAIHTTPBackend

[jackcook]

This PR adds the remove_from_body parameter to OpenAIHTTPBackend, which allows users to remove keys from the body of requests made to the OpenAI server. This is needed for us to profile tokasaurus, which does not support the max_completion_tokens or stream parameters.

[nm-red-hat-upstream-automation-bot]

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[Copilot]

Pull Request Overview

This PR introduces the remove_from_body parameter to OpenAIHTTPBackend to allow users to specify keys that should be removed from the request payload, addressing compatibility with tokasaurus.

• Added extra_body and remove_from_body parameters to the init method with corresponding docstring updates
• Refactored payload generation in _completions_payload to incorporate the removal of specified keys
• Renamed the _body helper to _extra_body for clarity in its purpose

Comments suppressed due to low confidence (1)

src/guidellm/backend/openai.py:466

• [nitpick] Consider adding an inline comment here to explain the rationale for removing keys from the payload, providing context for future maintainers.

        if self.remove_from_body:

[nm-red-hat-upstream-automation-bot]

📦 Build Artifacts Available
The build artifacts (.whl and .tar.gz) have been successfully generated and are available for download: https://github.com/neuralmagic/guidellm/actions/runs/15850937815/artifacts/3392030461.
They will be retained for up to 30 days.