Syllabus: Jump To Today link redirects focus

Fixes CNVS-12796

Test plan:
- Open Syllabus.
- Click the Jump To Today link.
- Note that the browsers focus is moved to near the relevant row.
- Verify that the function still works as expected for sighted users.
- Using a screen reader, confirm that the virtual focus is also set correctly.

Change-Id: I2c14aeb25b3a2b1c638ec821cc1de61ecb9776b9
Reviewed-on: https://gerrit.instructure.com/34432
Tested-by: Jenkins <jenkins@instructure.com>
Reviewed-by: Jeremy Stanley <jeremy@instructure.com>
QA-Review: Clare Strong <clare@instructure.com>
Product-Review: Aaron Cannon <acannon@instructure.com>