Fix phpstan

Author: Dinamiko

modules/ppcp-local-alternative-payment-methods/src/LocalAlternativePaymentMethodsModule.php

@@ -540,9 +540,9 @@ public function handle_pwc_order_received_redirect(): void {
 	 */
 	private function is_rest_request(): bool {
 		// phpcs:ignore WordPress.Security.ValidatedSanitizedInput.InputNotSanitized
-		$request_uri = wp_unslash( (string) ( $_SERVER['REQUEST_URI'] ?? '' ) );
+		$request_uri = wp_unslash( $_SERVER['REQUEST_URI'] ?? '' );
 
-		return strpos( $request_uri, '/wp-json/wc/' ) !== false;
+		return is_string( $request_uri ) && strpos( $request_uri, '/wp-json/wc/' ) !== false;
 	}
 
 	/**