Sync from internal repo (2024/08/26)

[Swimburger]

• Add language_confidence_threshold to Transcript, TranscriptParams, and TranscriptOptionalParams.

  The confidence threshold for the automatically detected language.
  An error will be returned if the langauge confidence is below this threshold.

• Add language_confidence to Transcript

  The confidence score for the detected language, between 0.0 (low confidence) and 1.0 (high confidence)
  Using these new fields you can determine the confidence of the language detection model (enable by setting language_detection to true), and fail the transcript if it doesn't meet your desired threshold.

Learn more about the new automatic language detection model and feature improvements on our blog.