It downloads 2_videos for the same video.

[VAaRrUNn]

Subject of the issue

Whenever I use coursera-dl for downloading course, It downloads 2 videos for every video. For eg., if a video is titled first.mp4, coursera-dl downloads 2 videos named: first.mp4 and first-extended-description-mixed.mp4. The second file is just useless it just includes the description in audio form in start of the video. Because of this the video is downloading 2 times and taking a lot of data.

Your environment

• Windows 11 Home Single Language, version: 21H2
• Python version: 3.8.7 (cause coursera-dl dosen't work in the latest versions so.)
• coursera-dl version: 0.11.5

Steps to reproduce

Download any Coursera course from Coursera using the following command:
coursera-dl course_name
[NOTE: I have not included username and password cause I have made a coursera-dl.conf file which already contains it]

• Is the problem happening with the latest version of the script?
  If the latest version of coursera-dl is 0.11.5 then yes.

• Do you have all the recommended versions of the modules? See them in the
  file requirements.txt.
  Yes. I have all the recommended version of the modules.

• What is the course that you are trying to access?
  This happens on every course, I have downloaded so far. I downloaded "neural networks and deep learning" from the deep- learning specialization offered by Deeplearning.ai

• What is the precise command line that you are using (don't forget to obfuscate
  your username and password, but leave all other information untouched).
  coursera-dl neural-networks-deep-learning

Expected behaviour

You should see 2 videos for every video that is in the course.