Add modal for unsaved changes in llms.txt

[leonidasmi]

Context

Summary

This PR can be summarized in the following changelog entry:

• Improves the UX of the llms.txt settings, by informing the user that they have to save their changes in order for the file to be generated.

Relevant technical choices:

Test instructions

Test instructions for the acceptance test before the PR gets merged

This PR can be acceptance tested by following these steps:

• In a site that has no llms.txt file, go to Yoast settings->llms.txt
• Enable the main toggle to enable the feature but dont save
• Click the View the llms.txt file button
• Confirm that you get the following modal:

• Discard it either from the close button or from the Got it button or from clicking outside of it.
• Save the changes, click the View the llms.txt file button and confirm that you're redirected to see the actual file
• Do any other change in the llms.txt settings and repeat the test. You should be getting the modal every time you change something and not save the changes yet.
• Disable the feature and dont save
• Confirm that the View the llms.txt file button is disabled now.

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:

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 #

[coveralls]

Pull Request Test Coverage Report for Build d7e7f2ca28a0c1e315ec43eee8f88b19c9ce529c

Details

• 0 of 7 (0.0%) changed or added relevant lines in 2 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage decreased (-7.9%) to 41.644%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
packages/js/src/settings/routes/llms-txt.js	0	3	0.0%
packages/js/src/settings/components/llms-txt-unsaved-changes-modal.js	0	4	0.0%

Totals
Change from base Build f318d2b3ed90c17a34ff4866d615e35c84c87444:	-7.9%
Covered Lines:	22164
Relevant Lines:	49748

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💛 - Coveralls

[vraja-pro]

CR & AC ✅