Fix send_request_cls declaration in ToastAlimtalkSendManager

Author: MU-Software

runtime/chalicelib/send_manager/toast_alimtalk.py

@@ -20,7 +20,7 @@ def _send_request_to_toast_request_payload(req: sendmgr_interface.SendRequest) -
 
 class ToastAlimtalkSendManager(sendmgr_interface.SendManagerInterface):
     template_manager = toast_alimtalk_template_mgr.toast_alimtalk_template_manager
-    send_request_cls: sendmgr_interface.SendRequest
+    send_request_cls = sendmgr_interface.SendRequest
     client = toast_alimtalk_client.ToastAlimTalkClient()
 
     service_name = "toast_alimtalk"