[WIP] Universal (LLM-agnostic) context machinery to support runtime LLM switching.

- Formatting fix + dead import cleanup

src/pipecat/frames/frames.py

@@ -403,10 +403,12 @@ class OpenAILLMContextAssistantTimestampFrame(DataFrame):
 
     timestamp: str
 
-# A more universal (LLM-agnostic) name for 
+
+# A more universal (LLM-agnostic) name for
 # OpenAILLMContextAssistantTimestampFrame, matching LLMContext
 LLMContextAssistantTimestampFrame = OpenAILLMContextAssistantTimestampFrame
 
+
 @dataclass
 class TranscriptionMessage:
     """A message in a conversation transcript.