fix: fix conversation title is overwrite empty (#39004)

Co-authored-by: autofix-ci[bot] <114827586+autofix-ci[bot]@users.noreply.github.com>

api/core/llm_generator/llm_generator.py

@@ -164,21 +164,22 @@ class LLMGenerator:
                 prompt_messages=list(prompts), model_parameters={"max_tokens": 500, "temperature": 1}, stream=False
             )
         answer = response.message.get_text_content()
-        if answer == "":
-            return ""
-        try:
-            result_dict = json.loads(answer)
-        except json.JSONDecodeError:
-            result_dict = json_repair.loads(answer)
-
-        if not isinstance(result_dict, dict):
+        if not answer.strip():
             answer = query
         else:
-            output = result_dict.get("Your Output")
-            if isinstance(output, str) and output.strip():
-                answer = output.strip()
-            else:
+            try:
+                result_dict = json.loads(answer)
+            except json.JSONDecodeError:
+                result_dict = json_repair.loads(answer)
+
+            if not isinstance(result_dict, dict):
                 answer = query
+            else:
+                output = result_dict.get("Your Output")
+                if isinstance(output, str) and output.strip():
+                    answer = output.strip()
+                else:
+                    answer = query
 
         name = answer.strip()
 

api/tests/unit_tests/core/llm_generator/test_llm_generator.py

@@ -50,7 +50,7 @@ class TestLLMGenerator:
         mock_model_instance.invoke_llm.return_value = mock_response
 
         name = LLMGenerator.generate_conversation_name("tenant_id", "test query")
-        assert name == ""
+        assert name == "test query"
 
     def test_generate_conversation_name_json_repair(self, mock_model_instance):
         mock_response = MagicMock()