fix: Error handling for 'answer' variable (#1343)

Author: Prasanjeet-Microsoft

code/backend/batch/utilities/orchestrator/open_ai_functions.py

@@ -125,11 +125,18 @@ async def orchestrate(
                     prompt_tokens=answer.prompt_tokens,
                     completion_tokens=answer.completion_tokens,
                 )
+            else:
+                logger.info("Unknown function call detected")
+                text = result.choices[0].message.content
+                answer = Answer(question=user_message, answer=text)
         else:
             logger.info("No function call detected")
             text = result.choices[0].message.content
             answer = Answer(question=user_message, answer=text)
 
+        if answer.answer is None:
+            answer.answer = "The requested information is not available in the retrieved data. Please try another query or topic."
+
         # Call Content Safety tool
         if self.config.prompts.enable_content_safety:
             if response := self.call_content_safety_output(user_message, answer.answer):