Lecture attachments not saved

Steps to reproduce the issue:

1. create a live course

2. open the “Content” section

3. add a new Chapter

4. edit the new Lecture

5. click on “Insert attachment” and select a video

6. wait for the upload to complete

7. save the Lecture

8. edit the new Lecture again

Expected behaviour: the list of attachments contains the video previously added

Actual behaviour: the list of attachments is empty

https://sharing.clickup.com/clip/p/t9004002740/f4f736e7-432b-4c48-995a-a1fb976dd879/screen-recording-2025-04-24-15%3A38.webm

Cause: the FE is not sending the fileId of the video when saving the Lecture (PATCH /courses/{courseId}/chapters/{chapterId}/lectures/{lectureId})