fix: ensure empty summary model skips compression

Co-authored-by: Fu-Jie <33599649+Fu-Jie@users.noreply.github.com>

plugins/filters/async-context-compression/async_context_compression.py

@@ -914,11 +914,7 @@ class Filter:
             # 3. Check Token limit and truncate (Max Context Truncation)
             # [Optimization] Use the summary model's (if any) threshold to decide how many middle messages can be processed
             # This allows using a long-window model (like gemini-flash) to compress history exceeding the current model's window
-            summary_model_id = (
-                self.valves.summary_model
-                or body.get("model")
-                or "gpt-3.5-turbo"
-            )
+            summary_model_id = self.valves.summary_model or body.get("model")
 
             if not summary_model_id:
                 await self._log(