wp_ajax_health_check_is_in_debug_mode is not used, contains incorrect nonce check

[johnbillion]

The wp_ajax_health_check_is_in_debug_mode() function is not used because the is_in_debug_mode site health check is a direct one, not an async one, therefore this Ajax handler is not used.

In addition the nonce check in this function is incorrect. wp_verify_nonce() is called without its return value being checked, rendering it non-functional.

It looks like this function can be safely removed. Marking as needs a second opinion in case I missed something.

[johnbillion]

Can I get a second opinion on removing this function?

[Clorith]

Sorry about the late followup, yes it should be fine to remove this, it looks to be an accidental fragment of a previous implementation used in the plugin before it was merged to core.

[johnbillion]

In 49122:

Site Health: Remove an unused function that was erroneously added when the site health feature was introduced.

This function was and is never used as the is_in_debug_mode check is a direct one.

Fixes #50282