Support and clarify student engagement during second step

[xcompass]

At the stage of looking at peer explanations, it would be nice to see an explicit prompt of "Do you wish to reconsider your answer choice?" It's easy to breeze through it without actually questioning yourself, which defeats the purpose.

Maybe supporting the grading on correct answer help to solve this issue.

[lenglund]

• Update instructional text to "Step 2a) Read Other Student Answers" and "These are samples of other student answers picked at random for this question. Read them carefully to compare with your answer below."
• Change student answer headings to: "option" chosen because:
• Change wording from "(You chose this option)" to "(You chose this in Step 1)"
• Add "Step 2b) Compare Your Answer"
• Add student's own answer into the second step as text (visually separated)
• Include options to "update" or "submit" at the end of the second step
• Then if student chooses to update, progressively reveal the form
• Remove update option once update is chosen
• Move submit option below once update is chosen

New default look for Step 2 becomes:

If student chooses "Update Answer", new look for Step 3 becomes:

[jleong-openedx]

Additional point:

• Remove "After submitting your final answer, you will see the correct answer for this question.", from Student view

[lenglund]

Idea is to make the students stop and think at the second step.

Firas's suggestion:
Students see un-selected radio buttons again and have to re-choose their answer. Then we progressively reveal the rationale box again.

[lenglund]

Updates as requested in #144 override this UI.