Relevanssi <= 4.27.1 and Relevanssi Premium <= 2.30.2 - Authenticated (Contributor+) SQL Injection

Description

The plugin provides an Admin Search page that allows users with the `edit_posts` capability to run Relevanssi searches from the WordPress dashboard. The AJAX handler accepts a URL-encoded `args` parameter, parses it into a `WP_Query`, and then passes user-controlled taxonomy query data into Relevanssi's taxonomy restriction builder. The taxonomy value is sanitized as text but is not parameterized for SQL before being interpolated into a term taxonomy lookup query. This allows an authenticated contributor-level attacker to inject SQL through the Admin Search AJAX request and execute time-based blind SQL injection against the WordPress database.