Fix issue where n shortcut causes RCE to duplicate
Fix issue where n shortcut causes RCE to duplicate

fixes VICE-2936

Test Plan
1. Open legacy dicussions
2. Press N to trigger a new reply
3. Expected: Should only trigger one reply versus bug that would
cause multiple responses to show

Change-Id: I65708e0c924a10fcb93714f693410e8935d6c435
Reviewed-on: https://gerrit.instructure.com/c/canvas-lms/+/296550
Tested-by: Service Cloud Jenkins <9144042a601061f88f1e1d7a1753ea3e2972119d@instructure.com>
Reviewed-by: Caleb Guanzon <54fa1f30d451e4f3c341a8f3c47c9215fd0be9c6@instructure.com>
Product-Review: Caleb Guanzon <54fa1f30d451e4f3c341a8f3c47c9215fd0be9c6@instructure.com>
QA-Review: Jason Gillett <12d37bea14b8257b31fd2f970455158adbd46adb@instructure.com>
QA-Review: Chawn Neal <908eabd8c84ff6c7c139535b8d37802d58ad1683@instructure.com>

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