Fix rgb color picker focus ring
Fix rgb color picker focus ring

closes CORE-3045

test plan
  - load the rce
  - click on text color or background color
  - click on the palette icon in the lower-right corner
  - focus on each of the text input boxes
  > expect the focus ring to be fully visible

Change-Id: I33deae968a93bff2cd001607394b84a1d7e73cf5
Reviewed-on: https://gerrit.instructure.com/196792
Tested-by: Jenkins
Reviewed-by: Steven Burnett <a0b450117c5d20a22d5c4d52bb8ae13adee003d8@instructure.com>
QA-Review: Steven Burnett <a0b450117c5d20a22d5c4d52bb8ae13adee003d8@instructure.com>
Product-Review: Ed Schiebel <0ca8a83847a5889cf05cb219c0ab09f6b646243b@instructure.com>

instructure/canvas-lms,instructure/canvas-lms,instructure/canvas-lms,sfu/canvas-lms,sfu/canvas-lms,djbender/canvas-lms,instructure/canvas-lms,sfu/canvas-lms,sfu/canvas-lms,sfu/canvas-lms,instructure/canvas-lms,djbender/canvas-lms,djbender/canvas-lms,sfu/canvas-lms,instructure/canvas-lms,instructure/canvas-lms,sfu/canvas-lms,djbender/canvas-lms