Load fonts from style variations in the editor and the admin

[matiasbenedetto]

What:

Load fonts from style variations only in the editor and admin, not in the public frontend.

This is an alternative and probably simpler alternative to the Gutenberg PR: WordPress/gutenberg#65019 and it core port PR: #7570

Trac ticket: https://core.trac.wordpress.org/ticket/62231

Testing Instructions:

Try to load a style variation and check that the fonts referenced in those style variations load as expected.

I created a theme to test this quickly and visually:
font-variants.zip
In this theme, the alternative font families and font faces with theme-relative URLs are defined in the style variations.

Sceencast

2024-10-17.11-10-40.mp4

[github-actions]

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Props mmaattiiaass, peterwilsoncc, ironprogrammer.

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[github-actions]

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[ironprogrammer]

Thanks for the PR, @matiasbenedetto! I've left some feedback on improving a unit test.

[peterwilsoncc]

This looks good to me and tests well.

I took the liberty of pushing some changes to the tests to allow for commit:

• fix the path to allow for testing on various systems per https://make.wordpress.org/hosting/test-results/ (and local dev environments that don't use docker)
• pushed a few docblocks to the tests

[peterwilsoncc]

Merged r59260 / ba47208

Thanks Matias.