CQS - ANIMATED answer distribution

Closes CNVS-16593

TEST PLAN
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  - go to new stats
  - look at the answer distribution chart
    + the bars should smoothly transition up the Y axis as the data is
      loaded
  - find a FIMB or Matching question
    + switch between the answer sets
      - watch the bars change around smoothly

Change-Id: Id2548bd0cc59e64d778393d16770dd95c088df10
Reviewed-on: https://gerrit.instructure.com/43615
Reviewed-by: Ryan Taylor <rtaylor@instructure.com>
QA-Review: Trevor deHaan <tdehaan@instructure.com>
Product-Review: Derek DeVries <ddevries@instructure.com>
Tested-by: Jenkins <jenkins@instructure.com>