new conversations: fix faculty journal option

fixes CNVS-10878

test plan:
  * enable faculty journal
  * open new conversations
  * compose a message
  * add one recpient
  * verify that new conversations has the same behavior as
      old conversations in showing and hiding the faculty
      journal checkbox when composing a message
  * verify that the message is added to the faculty journal
      if the checkbox is checked

Change-Id: Ifcb868021dcc96f368cf069e626e7a0a8a90561d
Reviewed-on: https://gerrit.instructure.com/32826
QA-Review: Braden Anderson <banderson@instructure.com>
Tested-by: Jenkins <jenkins@instructure.com>
Reviewed-by: Jon Willesen <jonw@instructure.com>
Product-Review: Braden Anderson <banderson@instructure.com>