fix: fix infinite retry loop in async_chat_streamly when success

The original code continues the retry loop even after a successful response.

rag/llm/chat_model.py

@@ -187,6 +187,9 @@ class Base(ABC):
                     ans = delta_ans
                     total_tokens += tol
                     yield ans
+
+                yield total_tokens
+                return
             except Exception as e:
                 e = await self._exceptions_async(e, attempt)
                 if e:
@@ -194,8 +197,6 @@ class Base(ABC):
                     yield total_tokens
                     return
 
-        yield total_tokens
-
     def _length_stop(self, ans):
         if is_chinese([ans]):
             return ans + LENGTH_NOTIFICATION_CN