Advanced Shipment Tracking for WooCommerce < 3.9.1 - Shop Manager+ SQL Injection via 'tracking_provider' Parameter

Description

The plugin is vulnerable to SQL Injection via the `tracking_provider` parameter of the `POST /wp-json/wc-ast/v3/orders/<order_id>/shipment-trackings` REST endpoint. This is due to insufficient escaping on the user-supplied parameter and lack of sufficient preparation on the existing SQL query in `WC_Advanced_Shipment_Tracking_Admin::get_provider_slug_from_name()` — the value is concatenated directly into the format string of `$wpdb->prepare()` rather than bound as a parameter, bypassing parameterised-query protections. This makes it possible for authenticated attackers, with Shop Manager-level access and above, to append additional SQL queries into the already-existing query that can be used to extract sensitive information from the database.