fix: Play audio of each composite word successively

[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 cloze exercises and comprehension exercises, answer options and words in the text can consist of multiple "atomic" words, creating a "composite" word. However, only the last words audio is played when proposing an answer or tapping the word in the sentence.

Steps to reproduce

1. Go to /lesson/16, i.e. 工作，工资,时间'
2. Click on any answer option containing a 千 character
3. Observe that only the last character's audio is played

Expected behavior

The audio of all the characters in the answer should be played, starting with the leftmost and ending with the rightmost, without overlapping audio.

Environment

• Device: PC
• OS: Ubuntu 22.04.3
• Browser: Chromium
• Version: 118