Implements different query for performance increase

[thijsoo]

Context

• This PR introduces a new query to calculate missing SEO_Link indexables.

Summary

This PR can be summarized in the following changelog entry:

• Introduces a performance increase when calculating how many SEO Links are missing props: @adconecto

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:

• Without this PR/RC make a site with lots of content 1000 posts and links. You can use the internal linking cli command shared here https://yoast.slack.com/archives/C03RAL4QPAQ/p1771490505341159 to make this happen. And the normal WP cli for the posts.
• Finish your SEOO and take not of the amount of indexables and SEO_links in the database.
• Install this PR/RC reset your SEOO and run it again and make sure the results are the same.

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.
• This PR also affects Yoast SEO for Google Docs. I have added a changelog entry starting with [yoast-doc-extension], added test instructions for Yoast SEO for Google Docs and attached the Google Docs Add-on 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.
• I have run grunt build:images and commited the results, if my PR introduces new images or SVGs.

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 f7993ca7282076fdcfd22a3feb035eb9d6b287d7

Details

• 4 of 4 (100.0%) changed or added relevant lines in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage decreased (-3.1%) to 53.184%

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Totals
Change from base Build f7234012bdf13a247018eec69d26e603a07a5027:	-3.1%
Covered Lines:	33227
Relevant Lines:	62469

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💛 - Coveralls