Update bottom bar text in lesson resources to say save on changes

[marcellamaki]

Summary

When resourcesChanged is true on the Mange Lesson Resources page, the button changes to say "save" instead of "close". It stays "close" when navigating through the folder structure, or when there are no changes.

References

Fixes #9473

Reviewer guidance

1. Navigate through the "manage lesson resources" flow
2. "Close" should appear by default
3. Selecting and/or deselecting resources should change the button to save

save-vs-close.mp4

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Testing checklist

• Contributor has fully tested the PR manually
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Reviewer checklist

• Automated test coverage is satisfactory
• PR is fully functional
• PR has been tested for accessibility regressions
• External dependency files were updated if necessary (yarn and pip)
• Documentation is updated
• Contributor is in AUTHORS.md

[radinamatic]

Two suggestions for improvements:

1. Change the string on the initial lesson creation page (title & recipients) from Save changes to Save, so it's consistent with the steps in Manage resources.
2. If a resource is selected, the button changes from Close to Save, but if that same resource is removed, the button still says Save. Shouldn't it return to Close, given that there are no changes to save?

[nucleogenesis]

Code lgtm!

[marcellamaki]

@radinamatic - updated! Let me know if this is what you were thinking

[radinamatic]

Yey, Save changes and Close are now switching back and forth as required! 💯

Tested by running from the source, let's figure out why the build is failing before merging.

[radinamatic]

Manual QA passed, just the build is failing.

[rtibbles]

This only changed JS code, and the JS part of the build completed successfully. The Python failure is fixed in the release-v0.15.x branch, so this is safe to merge.