Backport 59764 Add filter for duotone to account for gutenberg_restore_image_outer_container in classic themes

[ajlende]

Backport for WordPress/gutenberg#59764

Trac ticket: https://core.trac.wordpress.org/ticket/61271

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[ajlende]

From WordPress/gutenberg#59764 (comment)

So with the plugin active, both Gutenberg layout hook and the new duotone hook should be running. The duotone one runs after the layout one because of the order they're defined in

https://github.com/WordPress/gutenberg/blob/d7e80e65440fa019da8657e9e7d5b85a0dc45682/lib/load.php#L210

When this gets backported to core, the same should happen with the core version of the functions. Although, it looks like the imports will have to be reordered during the core backport (WordPress/wordpress-develop@9a616a5/src/wp-settings.php#L371).

In my opinion, with the way WordPress code is written with side effects in many files, the way that we mostly centralize imports, the size of the codebase, and the number of contributors, it makes more sense for use to just preserve the order of imports when backporting things to not have to worry so much about priority levels. It seems better to me to maintain that order than force extenders to use extra high priorities to override core behavior.

[tellthemachines]

This makes sense. Do we know why they were added to core in a different order in the first place?

We'll need to test that all these supports combined are still working as expected on this PR.

[tellthemachines]

I've tested the reordered block supports with both a classic and a block theme and there don't seem to be any changes.
The duotone filter is working as expected with aligned images on classic themes.
There are no changes for aligned images on block themes.

Code LGTM!

Given how close we are to Beta 1 I think it's OK to commit this as is but as a follow-up it would be nice to add a unit test for the new function

[tellthemachines]

Committed in r58313.