[NVDA] Messages - Settings gear is now navigable

You can now navigate the settings cog on individual messages in the
inbox.

Fixes CNVS-14013

Test Plan:

- open nvda
- select a message
- tab to the cog
- press enter
- navigate with up/down
- enter to select
- all items should work correctly

Change-Id: I36c9826f5073769a817dcae719d233c40e7bf652
Reviewed-on: https://gerrit.instructure.com/41586
Product-Review: Aaron Cannon <acannon@instructure.com>
Reviewed-by: Jayce Higgins <jhiggins@instructure.com>
Reviewed-by: Alex Boyd <aboyd@instructure.com>
QA-Review: Steven Shepherd <sshepherd@instructure.com>
Tested-by: Bryan Madsen <bryan@instructure.com>