Check for product by slug

[vraja-pro]

Context

Summary

This PR can be summarized in the following changelog entry:

• Fixes a bug where users without Yoast SEO Woo are not greeted with the AI upsell when trying to use the AI feature and are actually able to access the feature, if on a non-english site.
• Fixes a bug where woo SEO upsell would not render when on a locale that translate the product post label.
• Fixes a bug where the Schema type of the product would not be locked when Yoast SEO Woo is enabled.

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 Woo SEO and without Premium

• Change locale that changes the product label and edit a product.
• Schema and search appearance upsell
  • Check upsell ads for Woo SEO on search appearance and schema tabs - without this PR, the upsells would not appear
• Upsell Modal
  • Click on Use AI in the search appearance.
  • Check you see the upsell modal mention Woo SEO and Premium bundle - without this PR, the AI modal upsell would only mention Premium
  • Enable premium and click on Use AI again.
  • Check the upsell button now only mention woo seo - without this PR, we're actually not greeted with any upsell and the AI feature looks like it's starting to work
• With Woo SEO
  • Go to schema tab and check the page type is disabled - without this PR, the dropdown is enabled and the Default for Products option is pre-selected

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 Check for is cpt a product fails on locale that translate the product label

[leonidasmi]

CR + Acceptance is ✅