rename new disc. to redesign discussions
rename new disc. to redesign discussions

flag=react_discussions_post

fixes VICE-1475

test plan:
- verify change satisfies ticket

Change-Id: I56afdc47b428bb492f27eb7c9cc97ef89fc42e39
Reviewed-on: https://gerrit.instructure.com/c/canvas-lms/+/264936
Tested-by: Service Cloud Jenkins <9144042a601061f88f1e1d7a1753ea3e2972119d@instructure.com>
Reviewed-by: Omar Soto-Fortuño <2ca100155bc0669318a7e6f3850629c7667465e1@instructure.com>
QA-Review: Omar Soto-Fortuño <2ca100155bc0669318a7e6f3850629c7667465e1@instructure.com>
Product-Review: Omar Soto-Fortuño <2ca100155bc0669318a7e6f3850629c7667465e1@instructure.com>

sfu/canvas-lms,sfu/canvas-lms,sfu/canvas-lms,sfu/canvas-lms,sfu/canvas-lms,sfu/canvas-lms,sfu/canvas-lms