az network application-gateway settings list return empty list

### Describe the bug

According to the documentation, the following two parameters are required:

- --gateway-name
- --resource-group

Even when I run the command specifying the parameters as documented, I simply get an empty list returned.
The "Backend Settings" option under "Settings" > "Backend Settings" exists in the "Application Gateway" section of the Azure Portal web interface.

Is this a bug in the command?
Is this a documentation issue?

▼Documentation
https://learn.microsoft.com/en-us/cli/azure/network/application-gateway/settings?view=azure-cli-latest#az-network-application-gateway-settings-list

### Related command

az network application-gateway settings list --gateway-name [your application gateway name] --resource-group [your resource group name]

### Errors

no error, but return empty list.

### Issue script & Debug output

Executing according to the Related command

### Expected behavior

Please clarify whether this is a bug or a documentation issue and take appropriate action.

### Environment Summary

Since it is used for business purposes and is information, it cannot be taken out.

### Additional context

_No response_