move explanation location for grade notification checkbox
move explanation location for grade notification checkbox

fixes CNVS-30050

The "Include scores when alerting about grades" checkbox is not always
available, so the explanation of what that checkbox does should only be
available when it needs to be

Test Plan:
1)
* Make sure "Students can opt-in to receiving scores in email
  notifications" is enabled at the account level
* As a student, navigate to your notification preferences
  (/profile/communication)
* Hover over "Grading" (under "Course Activities") and verify that the
  hovertext does not end with "sensitive content will be sent outside
  of the institution."
2)
* Make sure "Students can opt-in to receiving scores in email
  notifications" is disabled at the account level
* As a student, navigate to your notification preferences
* Hover over "Grading" (under "Course Activities") and verify that the
  hovertext still does not end with "sensitive content will be sent
  outside of the institution."
* Verify that below the "Grading" item there is a checkbox alongside the
  string "Include scores when alerting about grades. If your email is
  not an institution email this means sensitive content will be sent
  outside of the institution."

Change-Id: I4d901beb23b56ce9c114322853dcf16e4af50c78
Reviewed-on: https://gerrit.instructure.com/83255
Reviewed-by: Joel Hough <4816dabf8db1bc6cac35b3a24cab2ff844b5b0c7@instructure.com>
Tested-by: Jenkins
QA-Review: Deepeeca Soundarrajan <5bcd4b623f00b7fc2942cd1c65c245b30a48a61f@instructure.com>
Product-Review: Andrew Huff <b334cc62d1472ff334a155064665c29200a80f59@instructure.com>

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