refactor: remove legacy assistant compatibility

backend/services/pipecat/processors.py

@@ -684,16 +684,6 @@ class KnowledgeRetrievalProcessor(FrameProcessor):
         self._last_signature = ""
 
     def _clear_context(self, messages: list[dict]) -> None:
-        # Remove the legacy Workflow knowledge message so an in-flight context
-        # created before this compatibility fix cannot keep sending that role.
-        messages[:] = [
-            message
-            for message in messages
-            if not (
-                message.get("role") == "developer"
-                and KNOWLEDGE_CONTEXT_MARKER in str(message.get("content") or "")
-            )
-        ]
         system_message = next(
             (message for message in messages if message.get("role") == "system"),
             None,