fix callback typing

deployments/templates/openim.yaml

@@ -315,7 +315,7 @@ iosPush:
 # Timeout in seconds
 # Whether to continue execution if callback fails
 callback:
-  url: "http://14.29.168.56:18889/sdkName"
+  url: ""
   beforeSendSingleMsg:
     enable: ${CALLBACK_ENABLE}
     timeout: ${CALLBACK_TIMEOUT}