add fallback to isAiFeatureEnabled

[vraja-pro]

Context

Summary

This PR can be summarized in the following changelog entry:

• Refactor check for if AI Feature is enabled.

Relevant technical choices:

• Moved the check from free to premium since it's a premium feature.
• Kept the original check as fallback.

Test instructions

Test instructions for the acceptance test before the PR gets merged

This PR can be acceptance tested by following these steps:

• Without Premium edit a post and check you have a Tab called "SEO analysis" that contain the analysis and a tab for "Premium SEO analysis" which is used as an upsell button.
• Enable Yoast Premium and check the tab label of "Premium SEO analysis" now contains the analysis and the "SEO analysis" is no longer there.
• Enable the AI feature and edit a post, check you can see the Fix assessments AI button when editing.
• Go to Yoast SEO -> Settings -> Site features and disable the AI feature.
• Edit a post and check you can't see the sparkle AI button anymore.
• Repeat test with https://github.com/Yoast/wordpress-seo-premium/pull/4529

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.

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 of
• 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 #21632

[coveralls]

Pull Request Test Coverage Report for Build 72cba33fad4193fedf671b5f99eb466751efb907

Details

• 1 of 5 (20.0%) changed or added relevant lines in 2 files are covered.
• 1 unchanged line in 1 file lost coverage.
• Overall coverage decreased (-0.003%) to 54.383%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
packages/js/src/components/contentAnalysis/SeoAnalysis.js	0	2	0.0%
packages/js/src/redux/selectors/preferences.js	1	3	33.33%

Files with Coverage Reduction	New Missed Lines	%
packages/js/src/components/contentAnalysis/SeoAnalysis.js	1	0.0%

Totals
Change from base Build b602854da9bd10c690131950c0472809c3328df6:	-0.003%
Covered Lines:	29939
Relevant Lines:	55466

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💛 - Coveralls

[pls78]

Acc: ⚠️
Both the SEO Analysis and the Premium SEO analysis are shown in the sidebar.

[pls78]

CR && Acc: ✅