[bug] Agent interrupts itself when on speaker phone

[scheda4fina]

Describe the bug
When using the flutter sdk with agent sdk if the agent is on speaker phone it interrupts itself whilst its talking. ie: it triggers the VAD system from its own voice. Note this only happens whilst the agent is on speaker phone.
This was reported in #633 but it's still not working on iOS with the latest version.

As mentioned the following setting might be broken?

    AudioCaptureOptions(
      deviceId: _selectedAudioDevice!.deviceId,
      echoCancellation: true,
      noiseSuppression: true,
      autoGainControl: true,
    ),

Or is this an issue in the livekit agent with the VAD and not related to the flutter livekit plugin?

To Reproduce
git clone the client-sdk-flutter and run the example
deploy a livekit agent in the cli
Connect to the agent room and switch to speaker phone.
Have the agent talk and observe the interruption detection being triggered by its own voice

Expected behavior
On speakerphone the agent shouldn't interrupt itself so that the conversation flow naturally.

Platform information
iOS 18.1.1 iPhone 14 Pro

• Flutter version:
  Flutter (Channel stable, 3.27.1, on macOS 14.5 23F79 darwin-arm64,
  locale en-US)
  • Flutter version 3.27.1 on channel stable at
  ...flutter
  • Upstream repository https://github.com/flutter/flutter.git
  • Framework revision 17025dd882 (5 weeks ago), 2024-12-17 03:23:09
  +0900
  • Engine revision cb4b5fff73
  • Dart version 3.6.0
  • DevTools version 2.40.2

• Plugin version:
  livekit_client: ^2.3.5
  livekit-agents>=0.12.8
  livekit-plugins-deepgram>=0.6.16
  livekit-plugins-openai[vertex]>=0.10.10
  livekit-plugins-silero>=0.7.4

• Flutter target OS:
  real device iOS 18.1.1 iPhone 14 Pro

• Flutter target OS version:
  real device iOS 18.1.1 iPhone 14 Pro