Fix: Ensure consistent audio MIME type

[9chait9]

Fixes #5552

This PR addresses issue #5552 by ensuring that the LiveRequestQueue.send_realtime method consistently sets the audio MIME type. If a types.Blob is passed without an explicit mime_type, it will now default to 'audio/pcm;rate=16000'. Existing mime_type values will be preserved.

Testing Plan

1. Set up a test environment: Configure the ADK with a LiveRequestQueue and a component that sends audio blobs.
2. Scenario 1 (No explicit MIME type): Send an audio blob using LiveRequestQueue.send_realtime without specifying the mime_type in the types.Blob object.
3. Verification 1: Inspect the outgoing request (e.g., using a network proxy or by logging within the LiveRequestQueue implementation) to confirm that the mime_type header or field for the audio blob is automatically set to 'audio/pcm;rate=16000'.
4. Scenario 2 (Explicit MIME type): Send an audio blob using LiveRequestQueue.send_realtime with an explicitly provided mime_type (e.g., 'audio/opus').
5. Verification 2: Inspect the outgoing request to confirm that the explicitly provided mime_type ('audio/opus') is preserved and used.

[adk-bot]

Response from ADK Triaging Agent

Hello @9chait9, thank you for creating this PR!

To help reviewers better understand and test your fix, could you please add a testing plan section to your PR description? Additionally, for bug fixes, providing logs or a screenshot demonstrating the fix would be very helpful.

This information will help reviewers to review your PR more efficiently. Thanks!

[9chait9]

Hi @adk-bot, thank you for the feedback! A detailed testing plan has already been included in the PR description. You can find it under the 'Testing Plan' section. Regarding logs/screenshots, this is an internal fix related to MIME type handling, which isn't easily demonstrated with screenshots. If specific logs are needed, please let me know, and I can provide them.

[rohityan]

Hi @9chait9, Thank you for your contribution! It appears you haven't yet signed the Contributor License Agreement (CLA). Please visit https://cla.developers.google.com/ to complete the signing process. Once the CLA is signed, we'll be able to proceed with the review of your PR. Thank you!

[9chait9]

@rohityan I have already signed CLA.

[9chait9]

@rohityan Friendly ping

[rohityan]

Hi @9chait9 , can you please bring branch to main and fix the failing tests.

[9chait9]

@rohityan, I have addressed the failing checks and brought the PR up to date with the main branch. The PR is now ready for your review. Thank you for your time and guidance!