refactor: use PROVIDERS_WITHOUT_RESPONSE_FORMAT constant from base_llm

Addresses CodeRabbit review: import the centralized provider blocklist
instead of duplicating a hardcoded set literal.

Author: tcconnally

lib/crewai/src/crewai/llms/providers/openai/completion.py

@@ -30,7 +30,7 @@
 
 from crewai.events.types.llm_events import LLMCallType
 from crewai.llms._finish_reason_utils import extract_choices_finish_reason_and_id
-from crewai.llms.base_llm import BaseLLM, JsonResponseFormat, llm_call_context
+from crewai.llms.base_llm import PROVIDERS_WITHOUT_RESPONSE_FORMAT, BaseLLM, JsonResponseFormat, llm_call_context
 from crewai.llms.hooks.base import BaseInterceptor
 from crewai.llms.hooks.transport import AsyncHTTPTransport, HTTPTransport
 from crewai.llms.providers.utils.common import safe_tool_conversion
@@ -1599,7 +1599,7 @@ def _prepare_completion_params(
         if (
             self.response_format is not None
             and self._extract_provider(self.model)
-            not in {"deepseek"}
+            not in PROVIDERS_WITHOUT_RESPONSE_FORMAT
         ):
             if isinstance(self.response_format, type) and issubclass(
                 self.response_format, BaseModel