## Summary

When calling ElevenLabs Speech-to-Text through LiteLLM, diarization-related request parameters do not appear to be honored/passed through to the upstream ElevenLabs `/v1/speech-to-text` API. This makes transcriptions come back without the expected speaker separation even when `diarize=true` and related ElevenLabs parameters are included.

## Expected behavior

LiteLLM should forward supported ElevenLabs Speech-to-Text multipart form fields to ElevenLabs, including at least:

- `diarize` - `tag_audio_events` - `timestamps_granularity` - `num_speakers` - `diarization_threshold` - `detect_speaker_roles` - `language_code`

ElevenLabs documents these fields for `POST https://api.elevenlabs.io/v1/speech-to-text` with `model_id=scribe_v2`.

Docs: https://elevenlabs.io/docs/api-reference/speech-to-text/convert

## Actual behavior

Calling the model through LiteLLM produced transcript output that did not include the expected diarization/speaker separation, even though the request included diarization settings. The same integration is being changed to optionally call ElevenLabs directly because the LiteLLM gateway behavior appears to be the source of the missing diarization.

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