Add-to-watchlist feature fails for a large class

[ragesoss]

The recently-implemented add-to-watchlist feature, accessible via a button on the Students tab of a course page, fails for this course: https://dashboard.wikiedu.org/courses/UCSF/Foundations_II_(Summer_2023)/home

This is probably because there are too many student user pages to be handled in a single request. It can probably be fixed by determining a reasonable maximum number of pages per request, and breaking large courses up across multiple requests.

[ragesoss]

@Abishekcs would you like to work on this?

[Abishekcs]

@ragesoss Sure :+1: