Unity SDK WebGL bridge export added

Minor Changes

• 062d715: Add @elevenlabs/client/internal/unity sub-path export for the Unity SDK's WebGL bridge.
  • New ./internal/unity entrypoint exposing MediaDeviceInput, MediaDeviceOutput, attachInputToConnection, attachConnectionToOutput, and setWebRTCAudioAdapterFactory as runtime values, plus WebRTCAudioAdapter, AnalysisResult, MediaDeviceInputConfig, MediaDeviceOutputConfig, and WebRTCConnectionConfig as type-only exports.
  • New named type aliases MediaDeviceInputConfig, MediaDeviceOutputConfig, and WebRTCConnectionConfig (the last replaces the previous ConnectionConfig, which is kept as a deprecated alias).