Don't allow users to set prerequisites on topics

[jayoshih]

Please remove any unused sections

Description

User should not be able to add prerequisites to topics

Issue Addressed (if applicable)

Addresses #1254

Steps to Test

• Add a thumbnail to a topic
• See if prerequisites tab appears

Checklist

• Is the code clean and well-commented?
• Has the docs label been added if this introduces a change that needs to be updated in the user docs?
• Have the changes been added to the CHANGELOG?
• Are there tests for this change?
• Are all user-facing strings translated properly (if applicable)?
• Are all UI components LTR and RTL compliant (if applicable)?
• Are there any new ways this uses user data that needs to be factored into our Privacy Policy?
• Are there any new interactions that need to be added to the QA Sheet?
• Are there opportunities for using Google Analytics here (if applicable)?
• If the Pipfile has been changed, is the updated Pipfile.lock file also included in this PR?
• Are the migrations safe for a large db (if applicable)?