Legacy discussion requests not properly serializing course_id

[blarghmatey]

When using the legacy discussions service (cs_comments_service) the in-line discussion block is throwing an error when trying to save the sort_ordering for an authenticated user. This is due to the course_id object getting passed through to the requests parameters unmodified, rather than getting converted to a string.

Relevant Sentry error: https://mit-office-of-digital-learning.sentry.io/share/issue/618f8150704f4a13b0cea9732b35dc56/

This was introduced in the commit 0d4281a and happens when hitting the code block here

[Ali-Salman29]

@blarghmatey

Thank You, we will look into this issue and get back to you soon.