Fix validation attribute for string parameter in Brave tool

Changed #[With(maximum: 500)] to #[With(maxLength: 500)] for the $query parameter since maximum is for numeric values while maxLength is for string length validation.

Author: OskarStark

src/agent/src/Toolbox/Tool/Brave.php

@@ -45,7 +45,7 @@ public function __construct(
      * }>
      */
     public function __invoke(
-        #[With(maximum: 500)]
+        #[With(maxLength: 500)]
         string $query,
         int $count = 20,
         #[With(minimum: 0, maximum: 9)]