When navigating resources for quiz/lesson-creation, unchanging elements in UI flash in and out

[jonboiser]

Observed behavior

Here's a GIF of what it looks like when you navigate the quiz-creation workflow

Observe that the entire middle part of the page disappears and reappears at each button-click, although its only the content cards that change.

There is a similar (but not identical) behavior on the Lesson-management workflow.

Expected behavior

The constant elements of the UI should stay in place and only a subset of the UI change at each navigation. We introduced a similar visual pattern in the import/export workflow, where e.g. the Channel Details at the top of the page remain in place while the list of topics below change.

User-facing consequences

A slightly better UX, since the UI elements that need to change is minimized.

Errors and logs

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Steps to reproduce

1. Use the search or browse functionality for creating/managing lessons/quizzes
2. See the majority of the UI flash in and out as you navigate resourecs.

Context

…

[rtibbles]

This should be resolved alongside updates to these flows to make them more consistent across quizzes and lessons and to include new metadata.