[Bugfix]: Fix the logic for deciding if tool parsing is used (vllm-project#8366)

Author: tomeras91

vllm/entrypoints/openai/serving_chat.py

@@ -607,7 +607,7 @@ async def chat_completion_full_generator(
 
             # if auto tools are not enabled, and a named tool choice using
             #   outlines is not being used
-            if not (self.enable_auto_tools
+            if (not self.enable_auto_tools
                     or not self.tool_parser) and not isinstance(
                         request.tool_choice,
                         ChatCompletionNamedToolChoiceParam):