processors(realtime-ai): add support for getting/updating LLM context

src/pipecat/frames/frames.py

@@ -158,6 +158,16 @@ class LLMMessagesFrame(DataFrame):
     messages: List[dict]
 
 
+@dataclass
+class LLMMessagesUpdateFrame(DataFrame):
+    """A frame containing a list of new LLM messages. These messages will
+    replace the current context LLM messages and should generate a new
+    LLMMessagesFrame.
+
+    """
+    messages: List[dict]
+
+
 @dataclass
 class TransportMessageFrame(DataFrame):
     message: Any