Tiled Gallery: Accessibility - when images are not interactive, remove button role and tabindex.

[coder-karen]

Fixes #39925

Proposed changes:

• This PR removes the button role and the tabindex that is added to Tiled Gallery images to help them be accessible (originally added here), but only in one scenario: when Carousel is disabled, and 'linkTo' is set to none.
• One option was to remove the tabindex and role conditionally from the relevant save.js file, but to prevent needing additional deprecation files as well as this only being a conditional change I opted to make this change when rendering the block via PHP.

Other information:

• Have you written new tests for your changes, if applicable?
• Have you checked the E2E test CI results, and verified that your changes do not break them?
• Have you tested your changes on WordPress.com, if applicable (if so, you'll see a generated comment below with a script to run)?

Jetpack product discussion

#39925

Does this pull request change what data or activity we track or use?

No.

Testing instructions:

Replicating the issue:

1. On a test site (WoA / self-hosted), ensure the full-screen Carousel option is disabled under Jetpack > Settings > Writing: /wp-admin/admin.php?page=jetpack#/writing
2. Create a new post and add a Tiled Gallery block.
3. Ensure 'None' is set for the 'Link to' option in the sidebar:

4. Save and preview
5. If you inspect the image source for one of the Tiled Gallery images, you'll see a tabIndex of 0, and role of button:

6. Click on any of the images - you'll see the image highlighted but no action taken
7. Similarly, tab onto one of the images and press enter. You'll see the image highlighted, but no action taken.
8. For all other options - images set to link to attachment type or media page, as well as Carousel enabled, you should be able to click on the image using a mouse and by tabbing and entering.
9. Changing between options and disabling / enabling Carousel should not result in any broken Tiled Gallery blocks.

Testing the fix

1. Repeat the above steps - step 8 should work as before, but for the testing steps where Carousel is disabled and the images set to link to 'none', you should not be able to tab onto the gallery images (nor see a role of button nor tabindex showing in the inspector for those specific gallery images).
2. Additionally, if you had a previously added Tiled Gallery, there should be no broken block messaging.

Simple testing

• Testing is not quite as easy on Simple - on trunk itself you may see a block validation error in the console upon adding a TG, saving, and refreshing the editor. However we can confirm the changes on the front-end, and that there is no visible broken TG in the editor itself with the changes (after applying the fix using the command in the generated comment below).
  • In Simple, the role="button" is what should be removed on the front-end when Carousel is disabled.
• On a Simple site, you can enable and disable Carousel from Settings > Media: /wp-admin/options-media.php

[github-actions]

Are you an Automattician? Please test your changes on all WordPress.com environments to help mitigate accidental explosions.

• To test on WoA, go to the Plugins menu on a WordPress.com Simple site. Click on the "Upload" button and follow the upgrade flow to be able to upload, install, and activate the Jetpack Beta plugin. Once the plugin is active, go to Jetpack > Jetpack Beta, select your plugin, and enable the fix/tiled-gallery-link-none-accessibility branch.

• To test on Simple, run the following command on your sandbox:

  bin/jetpack-downloader test jetpack fix/tiled-gallery-link-none-accessibility
  

Interested in more tips and information?

• In your local development environment, use the jetpack rsync command to sync your changes to a WoA dev blog.
• Read more about our development workflow here: PCYsg-eg0-p2
• Figure out when your changes will be shipped to customers here: PCYsg-eg5-p2

[github-actions]

Thank you for your PR!

When contributing to Jetpack, we have a few suggestions that can help us test and review your patch:

• ✅ Include a description of your PR changes.
  
• ✅ Add a "[Status]" label (In Progress, Needs Team Review, ...).
  
• ✅ Add testing instructions.
  
• ✅ Specify whether this PR includes any changes to data or privacy.
  
• ✅ Add changelog entries to affected projects
  

This comment will be updated as you work on your PR and make changes. If you think that some of those checks are not needed for your PR, please explain why you think so. Thanks for cooperation 🤖

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Jetpack plugin:

The Jetpack plugin has different release cadences depending on the platform:

• WordPress.com Simple releases happen semi-continuously (PCYsg-Jjm-p2).
• WoA releases happen weekly.
• Releases to self-hosted sites happen monthly. The next release is scheduled for none scheduled (scheduled code freeze on undefined).

If you have any questions about the release process, please ask in the #jetpack-releases channel on Slack.