Fetch and store all course work items for all active courses

Bug: b/282013130
Change-Id: I9c487e37c9a9033c041348fe7c57b891afd9a68f
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4557346


Reviewed-by: Toni Barzic <tbarzic@chromium.org>
Commit-Queue: Artsiom Mitrokhin <amitrokhin@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1149129}