Minor translation and aria clean-ups

Test plan:
- Visit the conference concluded page and verify that the accessible label on
  the pop-up menu is "Settings" and not "settings".
- Visit the New Conference page and verify that the Edit option in the pop-up
  menu no longer has an unnecessary aria-label.

Change-Id: I563b1a1a479b213253b65da4362bd5c050c4ec35
Reviewed-on: https://gerrit.instructure.com/34629
Tested-by: Jenkins <jenkins@instructure.com>
QA-Review: Steven Shepherd <sshepherd@instructure.com>
Reviewed-by: Liz Abinante <labinante@instructure.com>
Product-Review: Aaron Cannon <acannon@instructure.com>