fix: resolve mypy no-redef error for reasoning_content

Co-Authored-By: João <joao@crewai.com>

lib/crewai/src/crewai/llm.py

@@ -1234,7 +1234,7 @@ class LLM(BaseLLM):
         text_response = response_message.content or ""
 
         # Store reasoning_content for models that return it (e.g. DeepSeek thinking mode)
-        self.reasoning_content = getattr(
+        self.reasoning_content: str | None = getattr(
             response_message, "reasoning_content", None
         ) or (
             response_message.get("reasoning_content")
@@ -1751,7 +1751,7 @@ class LLM(BaseLLM):
             ValueError: If response format is not supported
             LLMContextLengthExceededError: If input exceeds model's context limit
         """
-        self.reasoning_content: str | None = None
+        self.reasoning_content = None
         with llm_call_context() as call_id:
             crewai_event_bus.emit(
                 self,