Add introductions seen route

[igorschoester]

Context

• Make it possible to mark an introduction as seen from JS (i.e. create a route).

Summary

This PR can be summarized in the following changelog entry:

• Adds an introductions seen route.

Relevant technical choices:

• Rename name to id as that seems like a better name for a "unique name"
• Use [\w-]+ matcher for the introduction ID in the route URL, as opposed to a query param without such regex limits. Mainly because this is more REST style

Test instructions

Test instructions for the acceptance test before the PR gets merged

This PR can be acceptance tested by following these steps:

• Deactivate Premium, instructions for with Premium are in the Premium PR
• Either test with Premium or find a way to send a POST request with the right credentials (nonce + cookie) and:
  • Send a request to /wp-json/yoast/v1/introductions/INTRO_ID/seen where INTRO_ID is the ID of your introduction
  • You can add a param is_seen to indicate whether you have seen it or not, if you skip this it will default to seen
  • You can verify the route worked by checking the user metadata: _yoast_wpseo_introductions

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 (Block/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:

• Introductions mechanism, though the only introductions still are the AI ones: upsell and Premium one. So all tests should be included in these features.

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.

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/141

[coveralls]

Pull Request Test Coverage Report for Build 6653889266

• 75 of 76 (98.68%) changed or added relevant lines in 7 files are covered.
• 591 unchanged lines in 1 file lost coverage.
• Overall coverage increased (+0.1%) to 49.199%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
src/introductions/domain/invalid-user-id-exception.php	0	1	0.0%

Files with Coverage Reduction	New Missed Lines	%
src/generated/container.php	591	0.0%

Totals
Change from base Build 6624478238:	0.1%
Covered Lines:	13213
Relevant Lines:	26856

---

💛 - Coveralls

[thijsoo]

one question 🚧

[thijsoo]

CR 👍

[vraja-pro]

ACC ✅