Remove overflow: hidden from #wrapper-container

It looks like the reason it was added is no longer present. This
allows for the side bar to scroll when its too big

Fixes CNVS-15888

Test Plan:

- Create 15+ assignments in a course with impending due dates (within a week)
- Publish these assignments
- As a student, view the to do list on the dashboard.
- Click 'view more' link is clicked
- you should now be able to see all of them

Change-Id: If6be938a29723c875114188c1178fa96bf59a96c
Reviewed-on: https://gerrit.instructure.com/42216
Tested-by: Jenkins <jenkins@instructure.com>
Reviewed-by: Chris Hart <chart@instructure.com>
Reviewed-by: Colleen Palmer <colleen@instructure.com>
QA-Review: Steven Shepherd <sshepherd@instructure.com>
Product-Review: Brad Horrocks <bhorrocks@instructure.com>