fix: make sure image scale CSS class is applied in editor

[laurelfulford]

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Changes proposed in this Pull Request:

Similar to #1706, this PR fixes an issue where the image scale S wasn't previewing in the editor.

I think both of these were kind of introduced here, but I can't, for the life of me, remember why those two sizes were excluded from the classes to begin with.

How to test the changes in this Pull Request:

1. Add a HPB to the editor, and align the images left or right.
2. Change the image size using the option in the sidebar, from L to XL, M, then S. Note that M and S are the same.
3. Apply this PR and run npm run build.
4. Rerun step 2 and confirm that S now previews correctly (should be ~25% of the available space).

Other information:

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[laurelfulford]

Thanks @dkoo!

[matticbot]

🎉 This PR is included in version 3.0.10 🎉

The release is available on:

• npm package (@latest dist-tag)
• GitHub release

Your semantic-release bot 📦🚀

[matticbot]

🎉 This PR is included in version 3.1.0-epic-ras-acc.8 🎉

The release is available on:

• npm package (@epic/ras-acc dist-tag)
• GitHub release

Your semantic-release bot 📦🚀