add explanation that some scores aren't graded yet in quiz attempt history

fixes CNVS-13255

test plan:
  - as a teacher
    - create a quiz with an essay question
    - take the quiz
    - the attempt history table should show an asterisk next to scores
      that are pending review, and a message that explains some questions
      aren't graded yet

    - create a quiz without an essay question
    - take the quiz
    - the attempt history table should NOT show an asterisk next to scores or
      an explanation that some questions not graded yet

  - as a student
    - take the essay quiz and we should have asterisks / message as well
    - take the quiz without essays, and we should not get asterisks/message

  - try this with multiple attempts as well. It should highlight any attempt
    that is pending review
  - this should work with both fabulous quizzes enabled / disabled

Change-Id: I7fd6b0744ca12ee1486a066d15b70701bbb22770
Reviewed-on: https://gerrit.instructure.com/35643
Tested-by: Jenkins <jenkins@instructure.com>
Reviewed-by: Ahmad Amireh <ahmad@instructure.com>
QA-Review: Caleb Guanzon <cguanzon@instructure.com>
Product-Review: Derek DeVries <ddevries@instructure.com>