accessibility fixes to kyle menus

fixes CNVS-9554

all items are properly read and focused when
navigating Kyle Menus via keyboard

this commit patches JQueryUI menu.js :(

test plan:

- Create a graded discussion.

- Activate the discussion cog menu, and confirm
  that all items are read by a
  screen reader, and properly focused on screen
  when arrowing up and down via the keyboard.

- Leave a reply, and test the cog menu on the
  reply as above.

- Confirm that all items within the menu are
  activatable by pressing enter

- Verify that the appearance of the page is still correct.

- Visit all other pages with Kyle Menus, and
  verify the same as above.

- make sure to test in IE since the way click
  events are simulated is different code

Change-Id: I735573b3151c1133b6bdfb2f0e6bea6b7a285372
Reviewed-on: https://gerrit.instructure.com/27447
Tested-by: Jenkins <jenkins@instructure.com>
Product-Review: Aaron Cannon <acannon@instructure.com>
Reviewed-by: Ryan Florence <ryanf@instructure.com>
QA-Review: Trevor deHaan <tdehaan@instructure.com>