Covers the 429 rate limi treached exception

[vraja-pro]

Context

Summary

This PR can be summarized in the following changelog entry:

• Fixes a bug where the AI free sparks upsell would appear instead of the rate limit error in cases where the rate limit for AI Generate was reached before the free sparks limit.

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:

• Edit a post with focus key phrase.
• Click on "Use AI" in the search appearance to generate title or descriptions.
• Grant consent and click on try for free on the upsell.
• Start generating, with out pausing (spam the Generate 5 more button).
• Check you get the Rate limit error.
• Close the modal and re open it
• Check you still get the Rate limit error and not the upsell.
• Activate Yoast SEO Premium subscription and try to spam the ai generator.
• Check you get the Rate limit error and not an upsell.

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 25.7-Major-Unexpected AI request rate limitation error even in few request

[coveralls]

Pull Request Test Coverage Report for Build ce02af59dbdbb66f1772e7a73189ae70bda542c8

Details

• 2 of 13 (15.38%) changed or added relevant lines in 6 files are covered.
• 1 unchanged line in 1 file lost coverage.
• Overall coverage decreased (-0.01%) to 52.641%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
src/ai-generator/user-interface/get-suggestions-route.php	0	1	0.0%
packages/js/src/ai-generator/components/suggestion-error.js	0	2	0.0%
src/ai-generator/user-interface/get-usage-route.php	0	2	0.0%
packages/js/src/ai-generator/components/app.js	0	6	0.0%

Files with Coverage Reduction	New Missed Lines	%
packages/js/src/ai-generator/components/suggestion-error.js	1	7.41%

Totals
Change from base Build d751249800b4348fa6a8edcca6edcb5466177f8b:	-0.01%
Covered Lines:	31032
Relevant Lines:	59710

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💛 - Coveralls

[leonidasmi]

Acceptance is ✅