Issue in execution of network virtual Appliance unit test

### Describe the bug

Trying to run test "azdev test --live test_network_virtual_appliance"

Currently, the test is under skip flag.

if I remove the skip flag, I am getting below error in execution.

> raise CLIError(msg)
E knack.util.CLIError: Unable to get extension index.
E Response body does not contain valid json. Error detail: The json response body exceeds the default limit of 128kb. Use '@AllowLargeResponse' on your test method to increase the limit or update test logics to avoid big payloads
[test_results.txt](https://github.com/Azure/azure-cli/files/12595482/test_results.txt)

### Related command

azdev test --live test_network_virtual_appliance

### Errors

E knack.util.CLIError: Unable to get extension index.
E Response body does not contain valid json. Error detail: The json response body exceeds the default limit of 128kb. Use '@AllowLargeResponse' on your test method to increase the limit or update test logics to avoid big payloads

src\azure-cli-core\azure\cli\core\extension\_index.py:57: CLIError

### Issue script & Debug output

test_result.xml attached

### Expected behavior

Test should execute

### Environment Summary

(venv) PS D:\Code\azcli\azure-cli> python --version
Python 3.11.5

### Additional context

_No response_