Revert "Update z-index hierarchy"

[renatho]

What?

Revert #65626

Why?

The original solution introduced a new issue. The reason is that a negative z-index will be behind any parent, which means that any parent with a background would be displayed on top of the image.

Testing Instructions

1. Create a group block.
2. Add a cover block inside the group with an image.
3. Add a background to the group (it could be through styles with a background or a normal background).
4. Make sure the image continues visible.

Screenshots or screencast

[github-actions]

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Co-authored-by: renatho <renathoc@git.wordpress.org>
Co-authored-by: aaronrobertshaw <aaronrobertshaw@git.wordpress.org>
Co-authored-by: juanfra <juanfra@git.wordpress.org>

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[aaronrobertshaw]

Thank you for the quick follow-up to this regression @renatho 🚀

Would you mind splitting this PR up into a simple revert of #65626 and one for the new approach?

My reasoning for the request is the regression is probably higher impact than the bug the original fix was for. A simple revert PR can land quicker.

Additionally, the new approach is a little more involved and could do with broader feedback, additional test coverage etc. Finally, splitting up this PR would also help make the history here cleaner and easier to follow for our future selves.

On the topic of tests, given the complexities around when the cover block should and shouldn't be visible due to z-index styling, it would be great if we could have some tests to protect against future regressions.

In the meantime, I'll give this PR a test in its current state.

[aaronrobertshaw]

I've now had a chance to take the new approach for a spin.

✅ I can replicate the regression on trunk in both the editor and frontend. (Apologies for missing that in my review of the original PR 🙏 )
✅ Confirmed that the navigation block is setup to add the .has-modal-open class on the frontend
✅ After checking out this PR branch, I can confirm both the original issue and the regression appear to be resolved

I'm not super familiar with the workings of the Navigation block, or the Interactivity API. Given the nav block relies on the interactivity API for applying the .has-modal-open class on the frontend, is there nothing for the editor side? Just wondering if we need to keep the editor and frontend closer together and more consistent.

I don't think that has to be a blocker but I'd like to get some extra eyes on this approach. cc/ @andrewserong

Before	After
Screen.Recording.2024-10-14.at.4.59.09.pm.mp4	Screen.Recording.2024-10-14.at.5.07.12.pm.mp4

P.S. I've added some labels to this PR and the other test failures look unrelated so I've kicked them off again.

[juanfra]

Thank you @renatho - the regression has been fixed.

Screen.Recording.2024-10-14.at.17.00.37.mov

[renatho]

Hi @aaronrobertshaw! 👋

Following your suggestion, I split the changes to merge this earlier. The new solution is in this PR: #66093.

I also update the PR description to match the purpose.

On the topic of tests, given the complexities around when the cover block should and shouldn't be visible due to z-index styling, it would be great if we could have some tests to protect against future regressions.

Working on an e2e test in the new PR.

[andrewserong]

Thanks for the ping! This appears to be a clean revert, and I think it's a good idea to get this PR in first for 6.7 and see how we go on the follow-up over in #66093

This change is testing well for me, and confirmed that it re-introduces the bug that was fixed in the original PR:

My reasoning for the request is the regression is probably higher impact than the bug the original fix was for. A simple revert PR can land quicker.

+1

LGTM!

[aaronrobertshaw]

I split the changes to merge this earlier. The new solution is in this PR: #66093.

Thanks @renatho, appreciate the effort and care here 👍

This appears to be a clean revert

Agreed. The code changes reflect #65626. Tests well for me also.

[github-actions]

I just cherry-picked this PR to the wp/6.7 branch to get it included in the next release: 9bba721