use object ref instead of array ref

Author: silvertonsoftware

library/ChatGPT.php

@@ -360,7 +360,7 @@ protected function handle_functions( stdClass $message, bool $raw_function_respo
         if( isset( $message->tool_calls ) ) {
             $function_calls = array_filter(
                 $message->tool_calls,
-                fn( $tool_call ) => $tool_call["type"] === "function"
+                fn( $tool_call ) => $tool_call->type === "function"
             );
 
             if( $raw_function_response ) {