Add post launch introduction

[pls78]

Context

• N/A

Summary

This PR can be summarized in the following changelog entry:

• Adds the post-launch introduction about Yoast AI Brand Insights and removes the pre-launch one.

Relevant technical choices:

• N/A

Test instructions

Test instructions for the acceptance test before the PR gets merged

This PR can be acceptance tested by following these steps:

• Use this Figma design as reference
• Start with just Yoast SEO activated
• With a MySQL client locate the wp_usermeta table
  • Find the row where meta_key = _yoast_wpseo_introductions and delete the content of the meta_value column: this would reset all the introductions you have previously seen
• Visit a Yoast SEO page
  • Confirm you see the introduction as in the design for Free
  • Confirm you don't see the pre-launch introduction ( Figma design [here](https://www.figma.com/design/
    OHKjiKm5cSAS7mzI4hK8dd/Introduction?node-id=1-2329&t=MQ5EbyIPwDdC5W5N-4))
  • Confirm the Discover Brand Insights now button points to https://yoa.st/ai-brand-insights-introduction-post-launch/
• Refresh and verify you don't get the introduction
• Activate Yoast SEO Premium
• Visit a Yoast SEO page and confirm you see the introduction as in the design for Premium
• Reset the introductions again
• Activate WooCommerce
• Confirm you see the same introduction as with Premium

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.

Impact check

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

• N/A

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 #770

[leonidasmi]

I haven't finished my review yet, but I'm mentioning it now to gain time @pls78

I think the naming has been finalized now and we can use the Yoast SEO AI+ one instead of the Yoast AI Brand Insights?

We do need to have UX give their thumbs up on the copy changes, but we can point them to the RC next week for that

[pls78]

I haven't finished my review yet, but I'm mentioning it now to gain time @pls78

I think the naming has been finalized now and we can use the Yoast SEO AI+ one instead of the Yoast AI Brand Insights?

We do need to have UX give their thumbs up on the copy changes, but we can point them to the RC next week for that

I think Yoast AI Brand Insights is the feature, while Yoast AI+ is the tier the feature belongs to. I'll double check now

[leonidasmi]

CR + Acceptance is ✅

One thing before merging: I believe that if we are to remove the AI_Brand_Insights_Pre_Launch_Test class we should then add codeCoverageIgnore annotations to its respective AI_Brand_Insights_Pre_Launch class' methods.

I dont think it's blocking a merge, but I think it's worth to mention.