fix links on login page that are missing underline for kb user
fix links on login page that are missing underline for kb user

Fixes: CNVS-29803

test plan:
- as a kb user navigate to the login screen
- tab through the entire page to ensure the links at the bottom
  show underline for kb focus
  (ensure the underline still shows on hover for non-kb user)

Change-Id: I759c7de2c7319dfec6eeb31cdb23eb44eb6c653f
Reviewed-on: https://gerrit.instructure.com/82609
Reviewed-by: Stephen Jensen <af2501a686d970a4ae53690c2b6f7e448f31f7df@instructure.com>
Product-Review: Blake Simkins <b120bacfd01287a1de7e8077d020b48e9650385b@instructure.com>
Tested-by: Jenkins
QA-Review: Myller de Araujo <e5c7c5e1b7f2ce5e9870cc98ec52b20b3006cb48@instructure.com>

SwinburneOnline/canvas-lms,fronteerio/canvas-lms,fronteerio/canvas-lms,dgynn/canvas-lms,HotChalk/canvas-lms,venturehive/canvas-lms,grahamb/canvas-lms,sfu/canvas-lms,SwinburneOnline/canvas-lms,sfu/canvas-lms,venturehive/canvas-lms,djbender/canvas-lms,djbender/canvas-lms,grahamb/canvas-lms,grahamb/canvas-lms,HotChalk/canvas-lms,venturehive/canvas-lms,sfu/canvas-lms,matematikk-mooc/canvas-lms,dgynn/canvas-lms,djbender/canvas-lms,sfu/canvas-lms,instructure/canvas-lms,sfu/canvas-lms,instructure/canvas-lms,HotChalk/canvas-lms,venturehive/canvas-lms,matematikk-mooc/canvas-lms,grahamb/canvas-lms,fronteerio/canvas-lms,sfu/canvas-lms,instructure/canvas-lms,SwinburneOnline/canvas-lms,matematikk-mooc/canvas-lms,matematikk-mooc/canvas-lms,instructure/canvas-lms,sfu/canvas-lms,dgynn/canvas-lms,fronteerio/canvas-lms,HotChalk/canvas-lms,instructure/canvas-lms,instructure/canvas-lms,SwinburneOnline/canvas-lms,dgynn/canvas-lms,instructure/canvas-lms,grahamb/canvas-lms,djbender/canvas-lms