fix: Stop instructor audio when answer audio starts playing

[toshify]

• I did all of the following:
  • search for a solution in the discussions
  • search for duplicate or closed issues
  • read the bug report contributing guidelines

Describe the bug

In comprehension exercises, the instructor/HoneyBee audio continues to play simultaneously with audio for a selected answer when answering questions.

Steps to reproduce

1. Go to /lesson/12, i.e. '家庭，家里有'
2. Click on the continue button to get to the next stage
3. While the Honey Bee is "talking", click any answer
4. Observe that the audio of the proposed answer plays simultanously with the Honey Bee's "talking", and the Honey Bee's "talking" is not interrupted, paused or cancelled, but continues to play.

Expected behavior

The Honey Bee audio should stop playing before the audio of the proposed answer starts playing.

Environment

• Device: Any, tested on PC
• OS: Ubuntu 22.04.3 LTS
• Browser: Chromium
• Version: 118.0.5993.70