"Show answer" view has lots of extra whitespace for instructors

Description

Staff members using the "show answer" button get an inaccurate layout relative to what learners see: the staff view has a lot of unwanted and indelible white space.

Reproduction:
1. Create a unit with 2 or more problems - say a multiple choice and a checkbox problem.
2. When viewing live as Staff, click "show answer"
Expect: See screenshot - Explanation appears with minimal extra space
Observe: See screenshot - Vast empty block appears under explanation.

This seems to be an instructor-facing issue: When viewing the same page as a learner (and making the problem setting "Show Answer" = "Always") - the learner doesn't see extra whitespace.

Steps to Reproduce

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Current Behavior

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Expected Behavior

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Reason for Variance

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Release Notes

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User Impact Summary

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Assignee

Sofiya Semenova

Reporter

Jennifer Akana

Reach

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Impact

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Customer

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Partner Manager

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Groups with Read-Only Access

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Actual Points

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Category of Work

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Platform Map Area (Levels 1 & 2)

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Platform Map Area (Levels 3 & 4)

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Sprint

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Priority

CAT-3
Configure