disable 'download submissions' button for quizzes without file submit questions

In SRGB, the "Download all submissions" button will no longer show for
Quizzes that do not have any 'file submit' questions. Another ticket
has been opened to address the zipping issue:
https://instructure.atlassian.net/browse/CNVS-16142

fixes CNVS-15620

test plan:
  -Create a quiz with at least one question. Do not add any
    'file submit' questions to the quiz.
  -Publish the quiz
  -Take the quiz as a student
  -As a teacher, go to the Gradebook Individual View. In the Content Selection area, choose the quiz from the "select an assignment" dropdown
  -Verify that there is no "Download All Submissions" button in the Assignment Information section

Change-Id: I8618a9ada748b07b0f936748644db41417c501f9
Reviewed-on: https://gerrit.instructure.com/42364
Tested-by: Jenkins <jenkins@instructure.com>
Reviewed-by: Josh Simpson <jsimpson@instructure.com>
QA-Review: Amber Taniuchi <amber@instructure.com>
Product-Review: Hilary Scharton <hilary@instructure.com>