az aks mesh get-upgrades fails with a traceback if Istio AKS addon is disabled

[zioproto]

Describe the bug

Calling az aks mesh get-upgrades -g my-rg --name my-aks fails with a traceback when the Istio AKS add-on is disabled.

Related command

Calling `az aks mesh get-upgrades -g my-rg --name my-aks

Errors

The command failed with an unexpected error. Here is the traceback:
'NoneType' object is not iterable
Traceback (most recent call last):
  File "/opt/homebrew/Cellar/azure-cli/2.57.0/libexec/lib/python3.11/site-packages/knack/cli.py", line 233, in invoke
    cmd_result = self.invocation.execute(args)
                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/homebrew/Cellar/azure-cli/2.57.0/libexec/lib/python3.11/site-packages/azure/cli/core/commands/__init__.py", line 664, in execute
    raise ex
  File "/opt/homebrew/Cellar/azure-cli/2.57.0/libexec/lib/python3.11/site-packages/azure/cli/core/commands/__init__.py", line 729, in _run_jobs_serially
    results.append(self._run_job(expanded_arg, cmd_copy))
                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/homebrew/Cellar/azure-cli/2.57.0/libexec/lib/python3.11/site-packages/azure/cli/core/commands/__init__.py", line 698, in _run_job
    result = cmd_copy(params)
             ^^^^^^^^^^^^^^^^
  File "/opt/homebrew/Cellar/azure-cli/2.57.0/libexec/lib/python3.11/site-packages/azure/cli/core/commands/__init__.py", line 334, in __call__
    return self.handler(*args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/homebrew/Cellar/azure-cli/2.57.0/libexec/lib/python3.11/site-packages/azure/cli/core/commands/command_operation.py", line 121, in handler
    return op(**command_args)
           ^^^^^^^^^^^^^^^^^^
  File "/Users/saverioproto/.azure/cliextensions/aks-preview/azext_aks_preview/custom.py", line 2907, in aks_mesh_get_upgrades
    for page in upgradeProfiles.by_page():
  File "/opt/homebrew/Cellar/azure-cli/2.57.0/libexec/lib/python3.11/site-packages/azure/core/paging.py", line 83, in __next__
    self.continuation_token, self._current_page = self._extract_data(self._response)
                                                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/saverioproto/.azure/cliextensions/aks-preview/azext_aks_preview/vendored_sdks/azure_mgmt_preview_aks/v2023_10_02_preview/operations/_managed_clusters_operations.py", line 4442, in extract_data
    return deserialized.next_link or None, iter(list_of_elem)
                                           ^^^^^^^^^^^^^^^^^^
TypeError: 'NoneType' object is not iterable
To check existing issues, please visit:
https://github.com/Azure/azure-cli/issues

Issue script & Debug output

n/a

Expected behavior

It should fail or print an error without traceback.

Environment Summary

azure-cli 2.57.0

core 2.57.0
telemetry 1.1.0

Extensions:
account 0.2.5
aks-preview 1.0.0b5
alb 1.0.0
amg 1.2.9
containerapp 0.3.44
costmanagement 0.2.1
fleet 1.0.1
front-door 1.0.17
k8s-extension 1.6.0
monitor-control-service 0.4.1
rdbms-connect 1.0.4
serial-console 0.1.6

Dependencies:
msal 1.26.0
azure-mgmt-resource 23.1.0b2

Additional context

No response

[yonzhan]

Thank you for opening this issue, we will look into it.

[microsoft-github-policy-service]

Thanks for the feedback! We are routing this to the appropriate team for follow-up. cc @dyu1208, @FumingZhang, @andyliuliming.

[FumingZhang]

The result returned by the server is not valid, should be an empty list instead of null.

@deveshdama will take a further look

[deveshdama]

This fix has been released as part of extension aks-preview version 2.0.0b3.