At small sizes, unattempted questions in Exam History have no label/icon on their buttons

[jonboiser]

Example from

https://kolibri-beta.learningequality.org/en/coach/#/0ca0280c91ccb9a880d922914226557f/reports/quizzes/536037266b3db551fb2e779209f552cb/learners/592c37a3d163a3c03a9ae97b3d4f2831/questions/3/interactions/0

Small window

Medium window

Expected behavior

Questions without attempts are visible in the "Answer history" column at small window sizes.

Currently, it looks like it's empty because the responsive behavior is simply to hide the label and show the icon (and these questions do not have icons)

To fix this, we should use the not started icon, which must have been removed in the past.

Original comment:

This looks like a big improvement to responsiveness!

Quick question: it looks like there might be an issue with missing icons or unexpected empty space in the ExamReport and LearnerExerciseReport gifs – is this a known issue?

Originally posted by @indirectlylit in #8143 (comment)