93 remove snippet preview

[mykola]

Context

• SnippetPreview from the file yoastseo/src/snippetPreview is not used any more so it's deleted and corresponding functions that uses it also removed.

Summary

This PR can be summarized in the following changelog entry:

• [wordpress-seo] Remove unused SnippetPreview from the file yoastseo/src/snippetPreview and functions that uses this class.

Relevant technical choices:

• SnippetPreview removed as well as functions that uses it - mainly in app.js and test where this object is used.

Test instructions

Test instructions for the acceptance test before the PR gets merged

This PR can be acceptance tested by following these steps:

• Activate Yoast SEO free plugin.
• Run unit test and make sure that they are pass
• Do smoke test in Classic editor, Block editor, Elementor and Woocommerce and make sure that everything works as previous and no error in console

Relevant test scenarios

• [x] Changes should be tested with the browser console open
• [x] Changes should be tested on different posts/pages/taxonomies/custom post types/custom taxonomies
• [x] 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

• [x] QA should use the same steps as above.

QA can test this PR by following these steps:

• Same as above

Impact check

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

• Only unused code remove but it's better to do smock test with all integrations.

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

• [x] I have tested this code to the best of my abilities.
• [x] 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.
• [x] I have written this PR in accordance with my team's definition of done.
• [x] I have checked that the base branch is correctly set. - branch should be changed to trunk when remove templates PR is merged. https://github.com/Yoast/wordpress-seo/pull/21312

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 #93