Refactor indexable pages to query per scope

[igorschoester]

Context

• Fix some quirks with the page dropdowns.

Summary

This PR can be summarized in the following changelog entry:

• Fixes some quirks regarding the page dropdowns on the settings' LLMs.txt page.

Relevant technical choices:

The component uses its ID as scope to have its own query, status and results.
The global list is used to get the actual entities with the referral IDs (e.g. the scope stores the ids, not the pages).
Added a cleanup of the scope on unmount, this aborts any ongoing request and removes the scope from the store.

Now I could've just made this in the component instead of in the store. In the hope that it is useful for other places.
But it might be just polluting the global store with inner component data too 😅 Just trying something new I suppose.

Test instructions

Test instructions for the acceptance test before the PR gets merged

This PR can be acceptance tested by following these steps:

• Go to your llms.txt settings: /wp-admin/admin.php?page=wpseo_page_settings#/llms-txt
• Enable the feature and manual page selection
• Save
• To add a significant delay in these request, add the following in your PHP:
  • If you need/want more time, adjust the number at sleep, it is in seconds

add_action( 'rest_request_before_callbacks', function ( $response, $handler, $request ) {
	if ( $request->get_route() === '/yoast/v1/available_posts' ) {
		sleep( 1 );
	}

	return $response;
}, 10, 3 );

• Refresh the page
• Open the network tab in your console and filter on fetch/XHR for some easy insights if the requests are actually done or not
• Before the /available_posts?search=&_locale=user request finishes, click on an empty dropdown and confirm that you get a loading state with the Searching pages... message.
• Verify when the request is done you see the list of pages
• Slowly type in a field
• Verify you see searching
• When you stop typing and searching is done, it should show the pages or no pages found
• Deselect the field without having made a page selection
• Verify the field is the previously selected page
• Select the field
• Verify it show your query again only true if there is no selected page
• Click the clear button
• Verify it clears your query and starts searching again
• Add the following under the sleep( 1 ); line, but still above the bracket } line:
  • This will make searching for foo error

		if ( $request->get_param('search') === 'foo' ) {
			return new Reponse(
				[
					'code'    => 'rest_page_invalid_id',
					'message' => 'Invalid page ID.',
					'data'    => [
						'status' => 400,
					],
				],
				400
			);
		}

• Search for foo
• Verify it has a Failed to retrieve pages. status indication when the request finished

Relevant test scenarios

• Changes should be tested with the browser console open
• Changes should be tested on different posts/pages/taxonomies/custom post types/custom taxonomies
• Changes should be tested on different editors (Default Block/Gutenberg/Classic/Elementor/other)
• Changes should be tested on different browsers
• Changes should be tested on multisite

Test instructions for QA when the code is in the RC

• QA should use the same steps as above.

QA can test this PR by following these steps:

Impact check

This PR affects the following parts of the plugin, which may require extra testing:

UI changes

• This PR changes the UI in the plugin. I have added the 'UI change' label to this PR.

Other environments

• This PR also affects Shopify. I have added a changelog entry starting with [shopify-seo], added test instructions for Shopify and attached the Shopify label to this PR.

Documentation

• I have written documentation for this change. For example, comments in the Relevant technical choices, comments in the code, documentation on Confluence / shared Google Drive / Yoast developer portal, or other.

Quality assurance

• I have tested this code to the best of my abilities.
• During testing, I had activated all plugins that Yoast SEO provides integrations for.
• I have added unit tests to verify the code works as intended.
• If any part of the code is behind a feature flag, my test instructions also cover cases where the feature flag is switched off.
• I have written this PR in accordance with my team's definition of done.
• I have checked that the base branch is correctly set.

Innovation

• No innovation project is applicable for this PR.
• This PR falls under an innovation project. I have attached the innovation label.
• I have added my hours to the WBSO document.

Fixes https://github.com/Yoast/reserved-tasks/issues/656

[coveralls]

Pull Request Test Coverage Report for Build 6a28461c15e740ae122049bff5ca09d91b90aa2d

Warning: This coverage report may be inaccurate.

This pull request's base commit is no longer the HEAD commit of its target branch. This means it includes changes from outside the original pull request, including, potentially, unrelated coverage changes.

• For more information on this, see Tracking coverage changes with pull request builds.
• To avoid this issue with future PRs, see these Recommended CI Configurations.
• For a quick fix, rebase this PR at GitHub. Your next report should be accurate.

Details

• 0 of 59 (0.0%) changed or added relevant lines in 2 files are covered.
• 18 unchanged lines in 2 files lost coverage.
• Overall coverage decreased (-0.04%) to 53.576%

---

Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
packages/js/src/settings/components/formik-indexable-page-select-field.js	0	16	0.0%
packages/js/src/settings/store/indexable-pages.js	0	43	0.0%

Files with Coverage Reduction	New Missed Lines	%
packages/js/src/settings/store/indexable-pages.js	2	0.0%
packages/js/src/settings/routes/llms-txt.js	16	0.0%

Totals
Change from base Build 19fd45952aca24fa50e6935224a9e7f266ee2ee4:	-0.04%
Covered Lines:	30490
Relevant Lines:	57881

---

💛 - Coveralls

[github-actions]

A merge conflict has been detected for the proposed code changes in this PR. Please resolve the conflict by either rebasing the PR or merging in changes from the base branch.

[leonidasmi]

CR: 🏗️

A couple of remarks

[leonidasmi]

CR + Acceptance is ✅