Fix the UT for viptela

[Taarini]

Fix the mock for the raw response

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ERROR: test_delete_connected (test_viptela.test_rest_connector.test_delete_connected)
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Traceback (most recent call last):
  File "xxx/rest/src/rest/connector/tests/test_viptela.py", line 150, in test_delete_connected
    connection.delete(mount_point='temp')
  File "xxx/pyats/pkgs/async-pkg/src/pyats/async_/synchronize.py", line 117, in _wrapped
    return method(self, *args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "xxx/rest/src/rest/connector/libs/viptela/implementation.py", line 335, in delete
    log.info("Output received:\n{response}".format(response=response))
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "xxx/yang/ncdiff/src/yang/ncdiff/__init__.py", line 69, in _str_response
    if self.raw.version in http_versions:
       ^^^^^^^^^^^^^^^^
AttributeError: 'NoneType' object has no attribute 'version'

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ERROR: test_delete_connected_change_expected (test_viptela.test_rest_connector.test_delete_connected_change_expected)
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Traceback (most recent call last):
  File "xxx/rest/src/rest/connector/tests/test_viptela.py", line 169, in test_delete_connected_change_expected
    connection.delete(mount_point='temp')
  File "xxx/pyats/pkgs/async-pkg/src/pyats/async_/synchronize.py", line 117, in _wrapped
    return method(self, *args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "xxx/rest/src/rest/connector/libs/viptela/implementation.py", line 335, in delete
    log.info("Output received:\n{response}".format(response=response))
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "xxx/yang/ncdiff/src/yang/ncdiff/__init__.py", line 69, in _str_response
    if self.raw.version in http_versions:
       ^^^^^^^^^^^^^^^^
AttributeError: 'NoneType' object has no attribute 'version'

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ERROR: test_get_connected (test_viptela.test_rest_connector.test_get_connected)
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Traceback (most recent call last):
  File "xxx/rest/src/rest/connector/tests/test_viptela.py", line 108, in test_get_connected
    connection.get(mount_point='temp')
  File "xxx/pyats/pkgs/async-pkg/src/pyats/async_/synchronize.py", line 117, in _wrapped
    return method(self, *args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "xxx/rest/src/rest/connector/libs/viptela/implementation.py", line 210, in get
    log.info("Output received:\n{response}".format(response=response))
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "xxx/yang/ncdiff/src/yang/ncdiff/__init__.py", line 69, in _str_response
    if self.raw.version in http_versions:
       ^^^^^^^^^^^^^^^^
AttributeError: 'NoneType' object has no attribute 'version'

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ERROR: test_get_connected_change_expected (test_viptela.test_rest_connector.test_get_connected_change_expected)
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Traceback (most recent call last):
  File "xxx/rest/src/rest/connector/tests/test_viptela.py", line 128, in test_get_connected_change_expected
    connection.get(mount_point='temp')
  File "xxx/pyats/pkgs/async-pkg/src/pyats/async_/synchronize.py", line 117, in _wrapped
    return method(self, *args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "xxx/rest/src/rest/connector/libs/viptela/implementation.py", line 210, in get
    log.info("Output received:\n{response}".format(response=response))
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "xxx/yang/ncdiff/src/yang/ncdiff/__init__.py", line 69, in _str_response
    if self.raw.version in http_versions:
       ^^^^^^^^^^^^^^^^
AttributeError: 'NoneType' object has no attribute 'version'

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ERROR: test_post_connected (test_viptela.test_rest_connector.test_post_connected)
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Traceback (most recent call last):
  File "xxx/rest/src/rest/connector/tests/test_viptela.py", line 87, in test_post_connected
    connection.post(mount_point='temp',
  File "xxx/pyats/pkgs/async-pkg/src/pyats/async_/synchronize.py", line 117, in _wrapped
    return method(self, *args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "xxx/rest/src/rest/connector/libs/viptela/implementation.py", line 253, in post
    log.info("Output received:\n{response}".format(response=response))
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "xxx/yang/ncdiff/src/yang/ncdiff/__init__.py", line 69, in _str_response
    if self.raw.version in http_versions:
       ^^^^^^^^^^^^^^^^
AttributeError: 'NoneType' object has no attribute 'version'

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