fix: use running loop in audio helpers

[Ghraven]

Summary

• Replace asyncio.get_event_loop() with asyncio.get_running_loop() in audio helper async methods
• Keep the callback/executor loop reference tied to the active running loop

Problem

The audio helper methods are already async methods, but they currently call asyncio.get_event_loop() before using the loop for thread-safe callback notifications and executor work. get_event_loop() has legacy behavior in modern Python when no loop is set by policy; inside async code, get_running_loop() is the clearer and more precise API.

Before / After

Before, the helpers asked asyncio for the policy/current loop with get_event_loop().

After, they capture the loop that is actively running the coroutine with get_running_loop().

Verification

• python -m compileall -q src\openai\helpers\local_audio_player.py src\openai\helpers\microphone.py
• git diff --check