QLA - QuestionFlagged event

Closes CNVS-16801

TEST PLAN
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  - go to take quiz with at least 1 question
  - open console
  - flag a question
    + verify an event is submitted with the question's id and that it's
      flagged (a message should also be logged)
  - unflag it
    + verify the same event is submitted but this time with
      "flagged: false"
  - try flagging other questions, the submitted ID should change

Change-Id: I7a1b6ae3a0538050f6b5c8ea3a3d935cd50b0710
Reviewed-on: https://gerrit.instructure.com/44152
Tested-by: Jenkins <jenkins@instructure.com>
Reviewed-by: Ryan Taylor <rtaylor@instructure.com>
QA-Review: Trevor deHaan <tdehaan@instructure.com>
Product-Review: Ahmad Amireh <ahmad@instructure.com>