Replace last deprecated webpack plugin API usage
Replace last deprecated webpack plugin API usage

Test plan:
 - Tests pass

flag=none

Closes FOO-2565

Change-Id: Ie6a2e0543824150372c514cc2bdc559cf214e259
Reviewed-on: https://gerrit.instructure.com/c/canvas-lms/+/278063
Tested-by: Service Cloud Jenkins <9144042a601061f88f1e1d7a1753ea3e2972119d@instructure.com>
Reviewed-by: Ahmad Amireh <a53a33601b8dd9d06ae9e50f1f30fbe957aba866@instructure.com>
QA-Review: Ahmad Amireh <a53a33601b8dd9d06ae9e50f1f30fbe957aba866@instructure.com>
Product-Review: Ahmad Amireh <a53a33601b8dd9d06ae9e50f1f30fbe957aba866@instructure.com>

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