[back] twitterbot: fix attribute error when listing acceptable videos

[amatissart]

Description

Fixes error when calling python manage.py run_twitterbot --list

Checklist

• I added the related issue(s) id in the related issues section (if any)
  • if not, delete the related issues section
• I described my changes and my decisions in the PR description
• I read the development guidelines of the CONTRIBUTING.md
• The tests pass and have been updated if relevant
• The code quality check pass