Fix component input error. (#4231)

### What problem does this PR solve?

#4108

### Type of change

- [x] Bug Fix (non-breaking change which fixes an issue)

agent/component/base.py

@@ -480,7 +480,8 @@ class ComponentBase(ABC):
                     if q["component_id"].lower().find("answer") == 0:
                         for r, c in self._canvas.history[::-1]:
                             if r == "user":
-                                self._param.inputs.append(pd.DataFrame([{"content": c, "component_id": q["component_id"]}]))
+                                self._param.inputs.append({"content": c, "component_id": q["component_id"]})
+                                outs.append(pd.DataFrame([{"content": c}]))
                                 break
                         continue