Uses assert_called_with instead of called_with

[hiwakaba]

Hello, Please check my patch. In my environment of Python3.12, an error occurs at the following line. Here is a part of the error message.

>       assert conn.send.called_with(request)

test/test_client_async.py:223: 
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 

self = <MagicMock name='BrokerConnection.send' id='281473155611728'>
name = 'called_with'

    def __getattr__(self, name):
        if name in {'_mock_methods', '_mock_unsafe'}:
            raise AttributeError(name)
        elif self._mock_methods is not None:
            if name not in self._mock_methods or name in _all_magics:
                raise AttributeError("Mock object has no attribute %r" % name)
        elif _is_magic(name):
            raise AttributeError(name)
        if not self._mock_unsafe and (not self._mock_methods or name not in self._mock_methods):
            if name.startswith(('assert', 'assret', 'asert', 'aseert', 'assrt')) or name in _ATTRIB_DENY_LIST:
>               raise AttributeError(
                    f"{name!r} is not a valid assertion. Use a spec "
                    f"for the mock if {name!r} is meant to be an attribute.")
E               AttributeError: 'called_with' is not a valid assertion. Use a spec for the mock if 'called_with' is meant to be an attribute.

assert conn.send.called_with(request)

Two assertions exists at the above line. The first assertion called_with is called and then assert is called. At the first assertion, we should seem to use assert_called_with instead of called_with. Please see:
python/cpython#100690

Then, the arguments of assert_called_with should be request, blocking=False because KafkaClient internally calls send with them.
https://github.com/dpkp/kafka-python/blob/master/kafka/client_async.py#L539

The second assertion should be removed because assert raises an error when an assert statement fails and do nothing when the statement succeeds.

$ python3
Python 3.12.0b3 (main, Jun 21 2023, 00:00:00) [GCC 13.1.1 20230614 (Red Hat 13.1.1-4)] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> from unittest.mock import Mock,MagicMock
>>> req = Mock
>>> conn = Mock
>>> conn.send = MagicMock(return_value=True)
>>> conn.send(req)
True
>>> conn.send.assert_called_with(req)     <--- return nothing when assertion is a success.
>>> conn.send.assert_not_called()    <--- raise AssertionError only when assertion fails.
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/lib64/python3.12/unittest/mock.py", line 905, in assert_not_called
    raise AssertionError(msg)
AssertionError: Expected 'mock' to not have been called. Called 1 times.
Calls: [call(<class 'unittest.mock.Mock'>)].

Thanks in advance,
Hirotaka

---

This change is 

[wbarnha]

I'll revisit this as soon as #2378 is merged.

[hiwakaba]

@wbarnha Thanks for your works!