Inform the user about debugging constants

[Djennez]

Is your feature request related to a problem? Please describe.

With the release of WordPress 6.7, we saw a lot of sites outputting notifications due to a change in WordPress. This would only happen if a site had had WP_DEBUG and WP_DEBUG_DISPLAY set to true though.

Describe the solution you'd like

Introduce a notification (maybe with the new dashboard in WordPress) that would inform the user about the use of these DEBUG constants. Though this might sound like a technical issue that we should not care about, we should brand this as a "Warning, SEO issue detected" notification. Because outputting these notification on the front-end of your website will get picked up by search engines and therefore likely influence your SEO reputation (this is an assumption though).

Why do you think this feature is something we should consider for the Yoast SEO plugins?

A website in production should simply not have any debugging online, as it's both performance reducing (SEO again) as well as possibly cause unwanted debug to show up on the frontend (SEO and security related).

Additional context

Some examples of the DEBUG output influencing search results:

Google search results showing the notification was picked up

A notification showing up on the frontend of a website