az repos policy create: "Unable to build a model: Unable to deserialize to object"

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

## Describe the bug

**Command Name**
`az repos policy create
Extension Name: azure-devops. Version: 0.18.0.`

**Errors:**
```
The command failed with an unexpected error. Here is the traceback:
Unable to build a model: Unable to deserialize to object: type, AttributeError: 'dict' object has no attribute 'lower', DeserializationError: Unable to deserialize to object: type, AttributeError: 'dict' object has no attribute 'lower'
Traceback (most recent call last):
File "D:\a\1\s\build_scripts\windows\artifacts\cli\Lib\site-packages\msrest/serialization.py", line 1428, in _deserialize
File "D:\a\1\s\build_scripts\windows\artifacts\cli\Lib\site-packages\msrest/serialization.py", line 1193, in rest_key_case_insensitive_extractor
File "D:\a\1\s\build_scripts\windows\artifacts\cli\Lib\site-packages\msrest/serialization.py", line 1218, in attribute_key_case_insensitive_extractor
AttributeError: 'dict' object has no attribute 'lower'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
File "D:\a\1\s\build_scripts\windows\artifacts\cli\Lib\site-packages\msrest/serialization.py", line 620, in body
File "D:\a\1\s\build_scripts\windows\artifacts\cli\Lib\site-packages\msrest/serialization.py", line 1446, in _deserialize
File "D:\a\1\s\build_scripts\windows\artifacts\cli\Lib\site-packages\msrest/exceptions.py", line 51, in raise_with_traceback
File "D:\a\1\s\build_scripts\windows\artifacts\cli\Lib\site-packages\msrest/serialization.py", line 1428, in _deserialize
File "D:\a\1\s\build_scripts\windows\artifacts\cli\Lib\site-packages\msrest/serialization.py", line 1193, in rest_key_case_insensitive_extractor
File "D:\a\1\s\build_scripts\windows\artifacts\cli\Lib\site-packages\msrest/serialization.py", line 1218, in attribute_key_case_insensitive_extractor
msrest.exceptions.DeserializationError: Unable to deserialize to object: type, AttributeError: 'dict' object has no attribute 'lower'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
File "D:\a\1\s\build_scripts\windows\artifacts\cli\Lib\site-packages\knack/cli.py", line 231, in invoke
File "D:\a\1\s\build_scripts\windows\artifacts\cli\Lib\site-packages\azure/cli/core/commands/__init__.py", line 657, in execute
File "D:\a\1\s\build_scripts\windows\artifacts\cli\Lib\site-packages\azure/cli/core/commands/__init__.py", line 720, in _run_jobs_serially
File "D:\a\1\s\build_scripts\windows\artifacts\cli\Lib\site-packages\azure/cli/core/commands/__init__.py", line 712, in _run_job
File "C:\Users\piet.ubrich\.azure\cliextensions\azure-devops\azext_devops\dev\common\exception_handler.py", line 31, in azure_devops_exception_handler
reraise(*sys.exc_info())
File "D:\a\1\s\build_scripts\windows\artifacts\cli\Lib\site-packages\six.py", line 703, in reraise
File "D:\a\1\s\build_scripts\windows\artifacts\cli\Lib\site-packages\azure/cli/core/commands/__init__.py", line 691, in _run_job
File "D:\a\1\s\build_scripts\windows\artifacts\cli\Lib\site-packages\azure/cli/core/commands/__init__.py", line 328, in __call__
File "D:\a\1\s\build_scripts\windows\artifacts\cli\Lib\site-packages\azure/cli/core/commands/command_operation.py", line 121, in handler
File "C:\Users\piet.ubrich\.azure\cliextensions\azure-devops\azext_devops\dev\repos\policy.py", line 76, in create_policy_configuration_file
return policy_client.create_policy_configuration(configuration=configuration, project=project)
File "C:\Users\piet.ubrich\.azure\cliextensions\azure-devops\azext_devops\devops_sdk\v5_0\policy\policy_client.py", line 24, in create_policy_configuration
content = self._serialize.body(configuration, 'PolicyConfiguration')
File "D:\a\1\s\build_scripts\windows\artifacts\cli\Lib\site-packages\msrest/serialization.py", line 622, in body
File "D:\a\1\s\build_scripts\windows\artifacts\cli\Lib\site-packages\msrest/exceptions.py", line 51, in raise_with_traceback
File "D:\a\1\s\build_scripts\windows\artifacts\cli\Lib\site-packages\msrest/serialization.py", line 620, in body
File "D:\a\1\s\build_scripts\windows\artifacts\cli\Lib\site-packages\msrest/serialization.py", line 1446, in _deserialize
File "D:\a\1\s\build_scripts\windows\artifacts\cli\Lib\site-packages\msrest/exceptions.py", line 51, in raise_with_traceback
File "D:\a\1\s\build_scripts\windows\artifacts\cli\Lib\site-packages\msrest/serialization.py", line 1428, in _deserialize
File "D:\a\1\s\build_scripts\windows\artifacts\cli\Lib\site-packages\msrest/serialization.py", line 1193, in rest_key_case_insensitive_extractor
File "D:\a\1\s\build_scripts\windows\artifacts\cli\Lib\site-packages\msrest/serialization.py", line 1218, in attribute_key_case_insensitive_extractor
msrest.exceptions.SerializationError: Unable to build a model: Unable to deserialize to object: type, AttributeError: 'dict' object has no attribute 'lower', DeserializationError: Unable to deserialize to object: type, AttributeError: 'dict' object has no attribute 'lower'

```

## 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 repos policy create --config {}`

## Expected Behavior

## Environment Summary
```
Windows-10-10.0.19041-SP0
Python 3.8.9
Installer: MSI

azure-cli 2.23.0

Extensions:
azure-devops 0.18.0

```
## Additional Context