fix: allow notes within assignment section

[damon314159]

Because

Sometimes lesson notes are required during the assignment section, to ward off potential pitfalls, but the config does not allow this, as noted in PR #27157
This is a temporary solution to get by until a resolution of #27162

This PR

Makes the required change to the config

Issue

Closes #XXXXX

Additional Information

Pull Request Requirements

• I have thoroughly read and understand The Odin Project Contributing Guide
• The title of this PR follows the location of change: brief description of change format, e.g. Intro to HTML and CSS lesson: Fix link text
• The Because section summarizes the reason for this PR
• The This PR section has a bullet point list describing the changes in this PR
• If this PR addresses an open issue, it is linked in the Issue section
• If any lesson files are included in this PR, they have been previewed with the Markdown preview tool to ensure it is formatted correctly
• If any lesson files are included in this PR, they follow the Layout Style Guide