Inconsistent behaviour when listing Gen2 filesystems

### **This is autogenerated. Please review and update as needed.**

## Describe the bug

I can list the content of another FS with the same properties in this storage account, there is another one that always fails.
-------------------------------------------------------------------------------------------------------
**Command Name**
`az storage fs file list`

**Errors:**
```
'dict' object has no attribute 'iter'
Traceback (most recent call last):
storagev2/filedatalake/v2020_02_10/_list_paths_helper.py, ln 50, in _get_next_cb
return self._command(
v2020_02_10/_generated/operations/_file_system_operations.py, ln 442, in list_paths
raise models.StorageErrorException(response, self._deserialize)
azure.multiapi.storagev2.filedatalake.v2020_02_10._generated.models._models_py3.StorageErrorException: (AuthorizationPermissionMismatch) This request is not authorized to perform this operation using this permission.
RequestId:4223f5fa-801f-001b-0fca-c9cfb9000000
Time:2020-12-03T23:20:11.1879656Z

...

filedatalake/v2020_02_10/_shared/response_handlers.py, ln 94, in process_storage_error
for info in error_body.iter():
AttributeError: 'dict' object has no attribute 'iter'
```

## To Reproduce:
Steps to reproduce the behavior. Note that argument values have been redacted, as they may contain sensitive information.

- _Put any pre-requisite steps here..._
- `az storage fs file list -f {} --account-name {} --auth-mode {}`

## Expected Behavior

## Environment Summary
```
macOS-11.0.1-x86_64-i386-64bit
Python 3.8.6
Installer: HOMEBREW

azure-cli 2.15.1

```
## Additional Context