fix set_api_key bug (#191)

### What problem does this PR solve?

_Briefly describe what this PR aims to solve. Include background context
that will help reviewers understand the purpose of the PR._

Issue link:#[Link the issue here]

### Type of change

- [x] Bug Fix (non-breaking change which fixes an issue)
- [ ] New Feature (non-breaking change which adds functionality)
- [ ] Breaking Change (fix or feature that could cause existing
functionality not to work as expected)
- [ ] Documentation Update
- [ ] Refactoring
- [ ] Performance Improvement
- [ ] Test cases
- [ ] Python SDK impacted, Need to update PyPI
- [ ] Other (please describe):

api/apps/conversation_app.py

@@ -248,8 +248,10 @@ def chat(dialog, messages, **kwargs):
                                                    tkweight=1 - dialog.vector_similarity_weight,
                                                    vtweight=dialog.vector_similarity_weight)
         idx = set([kbinfos["chunks"][int(i)]["doc_id"] for i in idx])
-        kbinfos["doc_aggs"] = [
+        recall_docs = [
             d for d in kbinfos["doc_aggs"] if d["doc_id"] in idx]
+        if not recall_docs: recall_docs = kbinfos["doc_aggs"]
+        kbinfos["doc_aggs"] = recall_docs
     for c in kbinfos["chunks"]:
         if c.get("vector"):
             del c["vector"]